All builds begin with the fuel used because the fuel determines the static compression ratio and the static compression ratio determines the cam. So what fuel are you planning to use? Yes, have a good shop measure the block deck height at all four corners of the block.

 

The 1968 SB Chevrolet 350 CI engine in my 1962 Bel Air was rebuilt in 1969 with forged flat top pistons and 64 cc 1962 double hump heads, for 10.3:1 compression ratio, with about 170 lb cranking cylinder pressure. Until about 1990, the 350 ci engine ran excellent on 92 octane premium pump gas, according to the original owner.

I bought the 1962 Chevrolet Bel Air three years ago. I must use five gallons of VP, C-12 108 octane racing fuel and fifteen gallons of 92 octane premium pump gas at every fill up in order to avoid detonation. In the future, I expect to use more VP 108 octane racing fuel and less premium pump gas.

Pump gasoline has got worse over the years and it is not getting any better.

Keep that in mind when you choose the heads and the camshaft. A compression ratio of 9.5:1 is considered high by today’s standards.

 

You did say pump gas, so I assume pump premium.

Why would you buy pistons and then want to decide on compression ratio? Also you mentioned a balanced crank, but imply that you bought the rotating assembly piece-meal. Better to get a complete matched/balanced rotating assembly.

Blueprint 195 heads are not going to get you very far at the track. Why go to all the trouble of building a forged piston stroker motor for the drag strip and then put marginal heads on it. Get some good heads - the best ones you can afford. Profiler 210s or AFR 210s depending on your pocketbook. You won't be sorry.

Manual trans is not good for drag racing - only good for spinning street tires and breaking parts when you get a heavy vehicle to hook up. Automatic will require a good torque converter (not cheap). Rear end should have a full spool so not to break spider gears when the slicks hook.

You will not notice much difference in power between a 10.8:1 and 10.0:1 CR with a properly matched camshaft/heads.

Lots of things need decided and thought out before a camshaft is selected. How much is this vehicle going to weigh and what times/trap speeds do you intend to run? What RPMs will the engine be running at (before/after shifts). I don't think you are quite there yet, but there are a lot of people here that can help you when you can answer these questions.

 

90 percent of the power is in the cylinder head so spend everything you can there.
The heads will dictate much of the cam needed

 

Too many under optimized choices for a racer truck. But some of that depends on out for fun or out to win.

The pistons are for 5.7 inch rods, without putting Mallory metal in the crank this drives you to an externally balanced engine. This is OK on the street but for drag race rpms is hard on the center 3 mains as the shaft runs locally out of balance which puts a twist in the shaft that eats these bearings up fairly quickly. The 6 inch rod and piston almost always allows internal balance without having to add heavy metal in the counter weights. The 6 inch rod used a much shorter thus lighter piston which allows this. There is no such thing as a prebalanced crank unless you know the exact rod and piston weight it's balanced to, I'll explain why below.

As balance goes there is no such thing as buying balanced parts and ending up with a balanced crank assembly. The counterweights have to be modified to counter the weight of the specific rod and piston used. Different rods by type and manufacturer and the same goes for pistons have different weights that have to be specifically addressed in a balance shop. Crankshafts typically come with overbalanced counterweights that allow trimming their weight against any selected rod and piston combo by removing counterweight material. This is much less expensive than having to add heavy metal to the counterweights. This is drill and ream a hole in the steel counterweight then press in a heavy metal slug made of a tungsten alloy. This is expensive both in process and material cost.

Although rods and pistons are sold in 'balanced' sets what is actually meant by that is they are weight matched to some tolerance, usually a gram or two. This reduces the amount of material removal the balance shop needs to remove from the heavier pieces to match the lighter. For a competition engine 1 or 2 grams of separation is too much, the balance shop will get this into something more like .1 gram. Once these parts are equalized bob weights are prepared and assembled on the throws then the crank is spun to identify how much materialneeds to be removed (or added) from specific counter weights and where on the counterweights to bring the assembly into balance. There's a lot more to this, I'm just bouncing across the surface to save time.

Getting the crank assembly into internal balance allows the use of a neutral balanced damper which simplifies replacement if needed, with an external balanced crank the off balance damper is part of the balancing assembly, if it needs to be replaced the engine needs to be disassembled and completly rebalanced.

External balanced engines should use a high end damper like the Rattler as the lack of main bay to main bay balance adds a lot of harmonic twist to the crank to where when racing the much more improved damping capabilities of these high technology dampers really soaks up the twist moments running out the end of the shaft.

Your head selection would be OK for a street 383 motor, for a race motor not so much. I typically run 190 to 200 cc ports for street 350's. The 383 is happy with 200 to 220 on the street, for racing I look to 230 to 240 ports before taking the grinder to them.

Cam and compression walk together for best efficiency which is related to best power but not the same. You can run too much cam for the compression and still get plenty good power though not optimized but that will come with high fuel burn. For racing that isn't a big consequence, for a daily driver that's far from optimum in terms of fuel consumption and engine life. Racing with aluminum heads you can push the conventions to the high side which will better the power. This is something where you need to go to the online static/dynamic calculators with cam and compression specs and iterate their model to see what fits best.

Bogie

 

Thanks for the info! I'm trying to learn as much as possible. Looks like I'm just going to have a street motor for now because I don't know enough and have enough money. So I can throw out the idea of a pure drag racer. I'm in it for fun not to win and my main objective is to make it faster than it is right now. And I'm in it for the knowledge. I also want an engine that lasts a while. I definitely do not want an engine that doesn't last long.

I'm going to run 91 octane.

Pistons: I can send the pistons back if I need to but this is why I chose these pistons. With the pistons, rods, and cranks, my rotating assembly length is 9.0. And the pistons have a +7 volume. My block came machined with a minimum 9.01 deck. So I can deck the block to 9.0 giving me 0 clearance and a compression ratio of 10.86. I read a quench of .04 is good. So my quench would be the size of my compressed head gasket thickness.

Heads: I want to run these heads for now, and when I save up I can buy better ones

Crankshaft: I wasn't assuming it was a balanced assembly. I got each component of the rotating assembly because it allowed me to get what I wanted. I was able to choose the compression height of the piston and volume on top, stroker rods. I have also heard that they come not balanced very well. So I wasn't going to deal with that. My plan was to take my rotating assembly in to have it balanced. Thanks for the info on balancing! I have been watching and reading lots of stuff on it. I'm not to sure what they meant by internally balanced crankshaft when I purchased it. But I thought it was correct in some way so that it works out to be internally balanced by the machine shop. I found this on summit "Crankshafts are listed as internal or external balance. This doesn't mean it's already balanced. It just tells you how it's intended to be balanced. It must be checked with the specific piston and rod combination you use."
https://help.summitracing.com/app/a...a_id/4878/~/what’s-the-difference-between-internal-and-external-engine-balance?
So I need to figure out the bob weight of the rotating pistons and rods and compare it to the bob weight of the crankshaft.

Rods: I read that to run a .04 quench area I need steel connecting rods. And its a good idea if my compression ratio is 10.86. I did not want the 6 inch rod because I read that it increases the dwell time, and it pushes the wrist pin into the ring pack making the top of the piston thinner? and then effects which cam I need more because it increases detonation or pressure. not sure? So I thought it was getting too complicated. But that is interesting that it makes it so you dont have to use mallory. Maybe I could have gotten a heavier crank too? I should have done more research trying to get all the parts to have a lower bob weight compared to the crankshaft initial bob weight. But I was limited to the parts for their dimensions and stuff so I thought I would just pay to have it balanced.

So my plan of action would be get it decked to 9.00 and balance the rotating assembly?

 

Thanks for the info! I'm trying to learn as much as possible. Looks like I'm just going to have a street motor for now because I don't know enough and have enough money. So I can throw out the idea of a pure drag racer. I'm in it for fun not to win and my main objective is to make it faster than it is right now. And I'm in it for the knowledge. I also want an engine that lasts a while. I definitely do not want an engine that doesn't last long.

I'm going to run 91 octane.

It's real hard to have fun when you're working on the engine all the time. You can't even work on the chassis or body when the engine keeps having issues so this is a real solid plan.

Pistons: I can send the pistons back if I need to but this is why I chose these pistons. With the pistons, rods, and cranks, my rotating assembly length is 9.0. And the pistons have a +7 volume. My block came machined with a minimum 9.01 deck. So I can deck the block to 9.0 giving me 0 clearance and a compression ratio of 10.86. I read a quench of .04 is good. So my quench would be the size of my compressed head gasket thickness.[/QUOTE]

You're not wrong, but too much internet garbage has led you astray somewhat. There's nothing wrong with a 9.010 deck. It gives you room for later rebuilds and the most important aspect is flatness and finish for head gasket sealing. An extra .010 isn't going to make a difference for what you're trying to do.

[/QUOTE]Heads: I want to run these heads for now, and when I save up I can buy better ones.[/QUOTE]

There are already better ones on the market for the the same money. You just need to keep shopping.

[/QUOTE]Crankshaft: I wasn't assuming it was a balanced assembly. I got each component of the rotating assembly because it allowed me to get what I wanted. I was able to choose the compression height of the piston and volume on top, stroker rods. I have also heard that they come not balanced very well. So I wasn't going to deal with that. My plan was to take my rotating assembly in to have it balanced. Thanks for the info on balancing! I have been watching and reading lots of stuff on it. I'm not to sure what they meant by internally balanced crankshaft when I purchased it. But I thought it was correct in some way so that it works out to be internally balanced by the machine shop. I found this on summit "Crankshafts are listed as internal or external balance. This doesn't mean it's already balanced. It just tells you how it's intended to be balanced. It must be checked with the specific piston and rod combination you use."
https://help.summitracing.com/app/a...a_id/4878/~/what’s-the-difference-between-internal-and-external-engine-balance?
So I need to figure out the bob weight of the rotating pistons and rods and compare it to the bob weight of the crankshaft[/QUOTE]

That crank has a target bobweight of around 1850 grams.
Balancing is only around $200 and generally a good idea but keep in mind it's not a perfect science and a lot of assumptions are made that are debatable so again, for your intended goals with this, $200 is a good idea. Just don't get carried away wasting time looking for .5 grams. I'd shoot for something like 5 grams or less on the rods and 10 grams or less on the pistons.

Rods: I read that to run a .04 quench area I need steel connecting rods. And its a good idea if my compression ratio is 10.86. I did not want the 6 inch rod because I read that it increases the dwell time, and it pushes the wrist pin into the ring pack making the top of the piston thinner? and then effects which cam I need more because it increases detonation or pressure. not sure? So I thought it was getting too complicated. But that is interesting that it makes it so you dont have to use mallory. Maybe I could have gotten a heavier crank too? I should have done more research trying to get all the parts to have a lower bob weight compared to the crankshaft initial bob weight. But I was limited to the parts for their dimensions and stuff so I thought I would just pay to have it balanced.

So my plan of action would be get it decked to 9.00 and balance the rotating assembly?[/QUOTE]

Again, the internet has you filled with knowledge that misplaced.
A long rods does what you read, a long rod can change the needed cam specs, and even changes how the head performs. What YOU need to looking at is the main goal of lightening the pistons so the crank can be balanced internally.

You have too keep in mind what your trying to do and the cost and value of the time and knowledge of what your trying to do. You don't need to worry about minor things on a street or track fun toy if it the cost doesn't net you anything. Keep it within the application at hand.
For example, I would buy a custom cam for everything because for the extra $50, the HP to $$ ratio favors it in all engines even if it's just a grocery getter. However a $2500 set of ultralight dyers rods and $2500 38lb Wineburg crank in the same grocery doesn't make sense by dollars or functionality.
It's a balance game between picking quality parts that get the job done and expense plus the tolerances needed to get there.
The internet has you chasing .0001 and .5 grams and all that in 400hp engine but when .001 and 5 grams is plenty close enough in realty to net the same goals, .0001 is a waste of time and effort and expense trying to hold on to something that just doesn't have the impact.

 

I also don't know the answers to some of the questions.

I was thinking I could shift around 6,400 or what ever RPM makes me go faster.

 

Buy this. https://www.skipwhiteperformance.co...-chevy-383-short-block-kit-forged-75cc-dish-4030-pistons-scat-crank-rods_89381/

Add a Comp Cams XR276HR or Comp Cams XR282HR, an Air Gap manifold, and a 750 Holley/Quick Fuel 4-corner idle with vacuum secondaries. Use 1 3/4" headers.

Only thing holding you back will be your heads. You may need to change valve springs on these heads as AFAIK Blueprint heads come with valve springs that aren't really very strong.

 

I forgot to mention that I already purchased these heads a couple months ago so Im stuck with them for a while. In six months I will get some more money to get big heads.
What valve springs are reccomended?

 

Springs:

• Spring Pressure Open: 295-305 @ 1.225
  Spring Pressure Closed: 115-125 @ 1.800
  Outside Diameter of Outer Spring (in): 1.437 in.
  Dual Valve Springs
  Chromemoly Retainers
  7 Degree Valve Locks

Looks like these springs are the same ones that AFR specs for Hydraulic flat tappet. https://www.airflowresearch.com/content/spring-spec-sheet.pdf

 

Springs:

• Spring Pressure Open: 295-305 @ 1.225
  Spring Pressure Closed: 115-125 @ 1.800
  Outside Diameter of Outer Spring (in): 1.437 in.
  Dual Valve Springs
  
  

Comp Cams Valve Springs 986-16
Valve Springs, Dual, 1.430 in. Outside Diameter, 322 lbs./in. Rate, 1.150 in. Coil Bind Height, Set of 16
Installed Height (in): 1.750 in.
Seat Pressure at Installed Height (lbs): 132 lbs.
Open Height (in): 1.250 in.
Open Pressure (lbs): 293 lbs.

I'm really surprised but these really look like the same springs Blueprint has, but set up at slightly tighter installed height to get the higher seat pressure. So I have to back off on your needing the Comp Cams Springs. You might want to consider throwing a 0.040 or 0.050 shim under the Blueprint springs and checking for coil bind. If OK - go ahead and try running them.

Don't bother with the Vic Jr with the Blueprint heads. You will kill your low end with the single plane manifold and the heads will prevent any significant gains on the top end. These two cams work quite well in a 383 at 2500-6000 rpm - valvetrain is heavy with a hydraulic roller and it's difficult to spin them much above 6500. No need to spin it higher that 6000 if it can't breathe anyway.

I know I keep poo-pooing your heads so I will say this. What we are describing is a 400+HP 383 - maybe 425 HP, more or less. That should put a 4000# truck into the high 12 second bracket if you can get it to hook up and can keep the engine in it's power band. Go to good heads and this is a 500HP build. Personally I think you are going to destroy manual transmissions and clutches - and the original granny lo trans will be worthless at the track - better to go with an automatic and a good converter. At least get a rev limiter for when you miss a shift.

Remember that it takes probably 10HP for each 0.1 second faster - so that would be low 12's. Every 100# you shave off in weight knocks off another 10th - so lose 500# and go 0.5 sec faster. Could be a lot cheaper than building another 50 HP into the engine.

 

you are building this truck bass ackwards and will burn a tonne of money to be disappointed in the performance gained.
Start with the truck
set diff up for maximum traction and weight transfer. Build/buy transmission that is your final choice. TKO 600 might live. Get some racing tires. Use a cheapo/stock engine (3500)
put a cam in it (cheap solid lifter) that will take you to 5500 rpm

get lots of track time
get more track time
Plan the replacement engine as a drop in for a year in the future
probably a 540/auto
get to the track
learn to drive
make it reliable

 

Im not sure why I did it this way. But in the end I will probably have the same parts anyways so order is not that important to me. It will be cool to see how much faster it is when I put in a 5 speed transmission, then the rear gears. I'm not going to spend anything extra because Im going to use all the parts. If I buy a part I'm using it. I know buying two more engines is more money and time than buying one. I know it wont be that fast until I get the transmission,axle gears,tires, and suspension to hook up. All those parts are next on the list.

 

Thanks for the info!

The truck will be primarily for the track. I will drive it to the track though because I don't have a trailer and another big truck. I was thinking the RPM Air gap because it will be for the track. I also thought the air gap would help with the higher compression because it keeps the air and fuel mix at a lower temperature because its separated from the lifter valley, help with detonation? Maybe more brainwashing from the internet.

Choosing the right springs for a cam seems complicated. It depends on RPM and lift right? So the valves don't float at high rpm and don't bind with the lift?

What would I need for the 500 hp? Better heads and the vic jr, different cam? or just bigger heads and same cam and rpm air gap?

I'm considering getting the profiler heads or maybe those blueprint heads next size bigger than the one I got. They are both the same price. Since I'm already buying all this stuff it would only be 700 more to get 80 hp? Then I could start reducing weight on the truck. 500 hp is enough for me. So I would get the cheaper heads.

I'm going to try and find some money to buy the big heads.

 

Valve springs depend on a lot of things. Cam lobe profile (how fast it opens, as well as how far), valve train weight and RPM amongst others. Don't need the Vic Jr or a different cam - just the good heads.

 

Im with Richard on what he says above,,,
you are now asking silly questions,IE:
rpm VS rpm air gap VS Victor jr?
its not a solid question
when you build an engine you start with a piece of paper
plan a parts list
all the parts need to match, they all work together

You have to answer how much power you are going to squeeze from the plat form you choose.
dual plane intakes generally use bigger carbs than single planes
you randomly mentioned 750,,,,,,too small for either of the intakes (FOR RACING)

start with engine to use
then choose heads to flow enough air to get your hp requirements
now you calculate the rpm you need to get the power
higher rpm range requires a proper carb/manifold combo to mix fuel (or injection)
the camshaft is now chosen to give the valve timing required to breathe deeply enough to get the rpm required
if the engine is big enough to easily make the power you wont have to maximise the cr to the point of needing exotic fuels
headers primary size and tube length is tuned to help with best scavenging at operating rpms

this is where you start

easy "GUIDELINE" 1.5 hp/cubic inch is a borderline max for a race engine that could see limited street use

383 x 1.5 = 574.5 hp

road race engines are slightly lower as their cam timing specs are for a wider powerbands

 

Okay thanks for the information!

 

Do I need a small base circle cam for this block? I'm using the 1 piece roller block. Does the small base circle cam only apply to 383 strokers that use the 2 piece block?

 

Depends on the camshaft, the camshaft timing, and the rods used. Degree your camshaft and then test the clearance but be careful not to run the rods into the camshaft. I like to cut a double thickness of hard cardboard (like used for behind carbon copies) into a shape I can hold onto (about 11" long) while placing between the rod and cam lobe as they pass each other. Just lay it on the cam lobe and turn the crank. You need to do every one as only some can hit. These sheets of cardboard are 0.020" thick, so I ensure 0.040" clearance. Most of the aftermarket rods these days will clear a moderate lift camshaft that is not small base circle. My rods have cleared three very different camshafts in my 383. Don't forget P/V clearance too, especially with 1.6 rockers.

Sent from my Moto G (4) using Tapatalk

 

Cam to Crank center is the same on all the blocks.
Connecting rod to cam clearance is the issue with the stroker crank.

 

From your original post:



I also got scat forged steel connecting rods that are clearanced for the stroker,

 

Small base circle cams are not desirable if you don't need one. Positions lifters lower in the bores and also requires longer push rods

Sent from my Moto G (4) using Tapatalk

 

The only way to get more lift is make the base circle smaller. Otherwise the cam won’t fit in the cam bores.
Hence the need for bigger cam bores for lifts to .900ish.
Also, the bigger camshaft journals make for a stiffer cam.

 

Personally I would go with the https://www.summitracing.com/parts/cca-cl08-432-8 kit and buy a https://www.summitracing.com/parts/clo-9-3500tx9/overview/ But either would work. This way you get a much better timing chain for cheaper, and it's a lot more adjustable. Don't forget distributor takes a special gear for the roller cam (not bronze).

You can buy the OEM pieces for the cam and crank hardware from Summit. They will drop ship. Just figure out the GM part numbers for the cam plate, bolts, and rear main seal housing and enter into their search engine for the price. I think you can buy the parts new cheaper than $180. But maybe not...... Here's a good search engine with parts blow-ups https://www.wholesalegmpartsonline.com/productSearch.aspx

Not sure why you wold use a stock pan on such an engine as windage of the crank in the oil can eat up HP, but you could use it. I run a Milodon pan with Milodon pickup, oil slosh baffle, and windage tray. You can get the crank further away from the oil in a deep pan. This is minor and could be changed later.

 

Don't use used OEM roller lifters or OEM rockers with this build, If you use guideplates (and you should), your pushrods will need to be hardened. A good set of full roller rockers are in order. I have had good luck with Scorpion rockers, but any name brand ones will be just fine.

Actually I previously said to degree than cam and then check the clearance to the rods - that is just wrong. Check the clearance when first turning with the cam installed straight up - then degree it. If you don't end up with the cam installed straight up, then check clearances again.

Don't buy your pushrods until you have verified the proper length. I do the 90 degree of rocker to valve at mid-lift method (minimizes sweep across the valve stem and maximizes valve lift - but may end up with rocker roller tip not exactly centered on the valve stem), but different strokes are used for different folks (some want to put the roller in the center of the valve stem - this has little to do with proper rocker arm geometry and more upon the dimensions of the parts that are being used - still valve guide wear is minimized this way). You choose.

 

Thanks! I was thinking about buying the chain and sprocket separately so I could get higher quality for the same price. I wasn't sure which one would work. The notes on the chain and sprocket you suggested says it not compatible with oem cam. But it will work with that comp cam?

What type of metal gear should I use for the distributor? Can I change the gear out on my msd flamethrower HEI?

I wasn't sure about which oil pan to use because it needs to fit in my 72 gmc 2wd. I feel like there isnt that much room from the pan to the crossmember.
I thought you wanted your crank in the oil so it throws some oil under the piston to lube the cylinders and wrist pin?

Right now I only have stock early sbc stamped rockers (1.5) I have stock length hardened pushrods for the guide plates that came with the heads.

For now I think Im going to order the cam and lifters and the better timing chain and sprocket. then figure out which oil pump and pan to use. And just buy new parts instead of that used block.

 

Thanks! I was thinking about buying the chain and sprocket separately so I could get higher quality for the same price. I wasn't sure which one would work. The notes on the chain and sprocket you suggested says it not compatible with oem cam. But it will work with that comp cam?

What type of metal gear should I use for the distributor? Can I change the gear out on my msd flamethrower HEI?

I wasn't sure about which oil pan to use because it needs to fit in my 72 gmc 2wd. I feel like there isnt that much room from the pan to the crossmember.
I thought you wanted your crank in the oil so it throws some oil under the piston to lube the cylinders and wrist pin?

Right now I only have stock early sbc stamped rockers (1.5) I have stock length hardened pushrods for the guide plates that came with the heads.

For now I think Im going to order the cam and lifters and the better timing chain and sprocket. then figure out which oil pump and pan to use. And just buy new parts instead of that used block.

Sorry about the link to the wrong timing chain - I'm too used to 2 piece RMS blocks. I imagine that Cloyes has a corresponding P/N for this timing chain used on the 1 piece RMS block when using the step-nose roller cams. I see that you found it. Bogie can advise you on this particular item much better than I can. As far as the camshaft itself - yes that is a factory style step nose camshaft P/N.

If you download the PDF of the Comp Cams catalog, they list the recommended distributor gear to use with your particular cam. (Also Valve Springs, lifters, etc). Be aware there are two slightly different shaft sizes on SBC distributors and the gears are specific. You will need to match the shaft size on your flamethrower HEI distributor whatever that is. Yes, you can change it out.

Definitely don't want your crank in the oil. Some people put a higher capacity pan on and then run a quart lower to help with this during hard acceleration. Fitting an aftermarket pan/windage tray/slosh baffle/oil pickup in a full size pickup should be very easy if you choose to go that way.

Nix the stock rockers for sure - don't even try it with aluminum heads.

Aluminum heads usually take longer pushrods than stock. Also lifter seats for pushrods are sometimes different depths with different manufacturers. So pushrod length definitely needs be checked before you commit to a particular set of pushrods to use with a particular set of heads and lifters and cam. (stock pushrods/heads used self-aligning type rocker arms without guide plates or guide holes and the pushrods would not be hardened - so ??????? with what you have if they are stock pieces)

 

I'm trying to order 500 or 1000 dollars at a time on summit because they give 50 to 100 off. Thanks for all the help!

 

The chain and sprocket doesn't fit cam shafts with the thrust plate, and a stepped nose cam.

this one fits CLO-9-3545X9. But it says I cant use stock timing cover. I guess that would be okay because Im saving money anyways and I need a timing cover. I wanted to get one of the ones where I dont have to take off the oil pan to adjust cam timing/change cam.

does the comp cam have a stepped nose?

 

You have to watch the block. Those made for the factory roller cam have raised lifter blocks for the taller factory roller cam, on the main oil galley that runs in the center of the valley between the lifter blocks there will be three bosses tapped to accept the bolts that position the 'spider' bracket that keeps the lifter alignment devices called 'dog bones' in place. On the front of the block there is a pad built around and with the thrust surface that the timing gear in the traditional flat tappet block rides against, however, the factory roller block adds two ears to this that are drilled and tapped for the bolts that retain the factory roller cam's thrust. Factory roller blocks use the step nose cams. This requires a unique cam gear that is about 1/8th less thick in the hub to make space for the cam retainer plate.

The cam drive parts that fit the factory roller cam do not fit the flat tappet cam and vise versa. However, a flat tappet cam and components can be run in a roller cam block with no modification to the block. The factory roller and the non roller blocks can be fitted with a no thrust plate roller cam using a thrust button and lifters that are tied together in pairs with a link bar. These use the older pre 1987 timing set for the cam without a stepped nose. The older thrust button roller cams are often refered to as retro-rollers, these days to distinguish them from the factory or OEM roller

If you use an OEM roller cam you can run a double roller timing chain for the factory roller cam engines, but these often require the boss of the main oil galley where it protudes into the timing case to have its top relived to clear the backside of the gear.

The L31 Vortec plastic timing cover will not clear the double row chain. However, the Vortec block will accept the older pre 1987 timing covers which usually do clear double row timing chain sets for the factory roller cam, sometimes an extra timing case cover gasket or two is required for clearance.

My preference is to the cast aluminum mult-piece timing covers that allow cover removal without disturbing the pan seal. Sometimes these require an extra gasket or two to clear the gears and chain. The big limitation is the thicker cover will not fit behind the short coolant pump. The cast cover is much better at keeping the unsupported chin portion under the crank from leaking oil as stamped covers tend to do.

This is, or has become, a complicated subject, that I left off some options I don't think apply in your case so that saves what would be even more complication.

Read this more than once to be sure you understand it, ask questions if in doubt. The tech help line at most wheeler, deeler parts houses are clueless about this so don't expect 'help desk' help. You gotta go in already knowing.

The distributor gear term for factory and many aftermarket roller cams is a Melonized gear. These are steel with a surface treatment to prevent tooth galling with the materials roller cams have to be made from. This gear gives typical street long life which is lacking in bronze and composite gears, not that they can't be used but they will become an additional service item you get o replace very so often.

Bogie

 

What is a good clearance for the rods to the block and piston to crank counterbalances? The block I got is clearanced for the 3.75 stroke. But I want to check all the clearances.

The side of the rod cap gets the closest to the block. The piston also gets kinda close to the crank counterbalances.

 

That can get confusing. Thanks for the information! I kept getting bits and pieces from here and there but now I understand.

So an oem roller cam can't use a standard double roller. From this I'm guessing the oem roller block used a single roller or some special oem double roller? But definitely not the older style double roller. I'm assuming the cam https://www.summitracing.com/parts/cca-cl08-432-8 is a factory roller style. But the double roller https://www.summitracing.com/parts/clo-9-3545x9 is an aftermarket design that will clear the boss while using the cam thrust plate? But I have to use the two piece timing chain cover and possibly more gaskets? And the longer water pump.

The timing cover and water pump are okay because i need new ones anyways. And I'm running electric fans so the longer water pump wont be a big deal. I guess I might need to get a new pulley for the water pump to re align it. But those are cheap.


The cast timing cover seems like a good idea too. I recall that ford windsors have a cast aluminum timing cover.

 

This is my go to timng set for factory roller SBC's. It is reasonably priced, offers a little cam to crank adjustment, and from my experience excellent long life. So these are good street to mild track performance sets. The whine a little when new that settles down with time, they have replacement chains available but never have xperienced the need to change it out.

https://www.competitionproducts.com...ar-Double-Roller-250-Timing-Set-Chev-305-350/productinfo/SAG78150/#.XYT7X-tHarU

The factory roller cam uses a smaller bolt circle than factory flat tappet cams so the timing set does not interchange right at that point. The OEM roller cam gear has less thickness as well so it can accomodate the thickness of the thrust plate.

The flat tappet bolt lock does not fit the OEM roller cam either, the gear retention bolts use Locktite on their threads. You will also find that standard hex or Allen heads will not fit under the cover, you need to use the GM bolt specific to the factory roller cam's timng set or spend some time at your local fastener store hunting for shallow headed bolts.

As inexpensive and effective timing covers go this below is my choice, looks good, works well, doesnt cost a mint like CVR and some other big name covers.

https://www.jegs.com/i/Speedmaster/...265.1039/10002/-1?gclid=EAIaIQobChMI4P2V2-rf5AIVsiCtBh2HXAEvEAQYASABEgIil_D_BwE

Don't assume anything about fit if the discription doesn't includes words like "fits factory roller cam" or "fits OEM roller cam" it doesn't.

As far as rods go if you bought cap screw style rods rather than the more conventional bot and nut type the odds are real good that the cap screw rods will clear a standard diameter cam. If there is an issue dress the rod just enough to get .050 clearance. These undersize cams are made for factory style nut and bolt rods that can require a lot of grinding on the bolt head end for clearance. These undersized cams are subject to breakage as they are not as strong as the stock diameter cam which isn't as robust as it should have been to start with.


Bogie

 

They say 0.060" - 0.070" clearance on all things rotating. I only checked for 0.040+ between the cam/rods. My block was clearanced/notched by my machine shop.

Have you given up on the idea of the good heads? Just curious.