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Discussion Starter #1
Hello!
You can call me E for now i guess,

Im new to forums, I read them often but i never join to post anything because Im usually researching a different car and problem each time. Mostly I just harvest the bits and pieces i need to answer my query and leave the rest behind as I find that most of the time the question was asked wrong in the first place and or the thread turns into bickering over tire shine brand preference.
I have not noticed that to be the case in the threads I have read on your site. Thank you.



I joined because I am building myself a hot rod truck to go raise hell with on the weekends.
I think that I would benefit greatly from some of y'all s advice on certain matters if I had the opportunity to ask you, as well as help answer some questions about problems that you may be having with your vehicles.

About myself

I have over 25 consecutive years in the automotive trade as a tech and shop manager . I own my own shop in here in New England now for the past 7 years where we do from major repairs to maintenance on pretty much anything up to say a 1 ton truck.

Typically I do not get to mess around with old small blocks and classic cars as there is minimal demand out here in the trenches...



However, when asked ,most of the time I refuse to work on other peoples hot rods. (and I use that term loosely)

As far as the work that comes thru my shop goes I am simply more interested in production work on late model vehicles.

The old car projects take forever and are in constant need of attention because every 40 or 50 year old bolt has been molested over and over by god knows how many.And it gets more expensive than anybody is ever prepared for. Myself included.

I believe that having and driving something old and cool should be a labor of love and you do not get the cred if you have to pay people to work on it for you.
So I bought a nice 68 GMC truck from somewhere way south of here and ripped it apart. This looks like the second time for the body. The Crap 305 covered in auto zone parts got lost at sea so I am building this truck a proper engine.



So, regarding my trucks soon to be engine, a SB350.... I am currently lost scratching my head feeling overwhelmed in the camshaft aisle.
I have a lot of specs and sizes and ratios and stroke and torque converter and even tire size to consider when selecting a cam. Most of this information I have.

Master certified tech? Yes. Performance Engine Builder? No.
could somebody please help me get the ball rolling here.

Thanks E
 

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Hey..I'm new here too.. But wanted to suggest you might want to look at the Edelbrock kits. You pick the performance level you want..and go with their Performance matched set up . Heads, cam/lifters, intake..takes the guess work out of it..and you know exactly what you will end up with. I have used them on my last 3 projects and have been very happy. Plus their Tech support is awesome..
 

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Discussion Starter #4
here goes, hope i dont leave anything out. I have everything but the cam. the engine is a 350 4 bolt main. .030 over., 6 inch rods ,Venolia Popup pistons,3.75" stroke, new cast iron Dart 2.02in 1.94ex 76cc Heads, scorpion 1.5 rockers, Edelbrock 7501 air gap intake. looks like an edelbrock ??? cfm , The Math from my machinist whom I trust with all my customer work estimates this engine to have a 10.5 :1 compression ratio.

Now.... I got this engine with heads = 64cc 2.02in 1.94ex .It was supposed to be 12:1 almost 400 hp and ran on 110 octane down a drag strip for its brief life prior to being sold to me.

Essentially all I did was put bigger cc heads on it to lower the compression and hopefully run on pump gas 93 and I need to select a optimal camshaft and hydraulic lifters now.

Im going to run a TH350 manual valve body trans, with 3.55 rear.
I want it to have good vacuum for disk brake upgrade with booster.
Good Idle quality when in gear. I would prefer to not run a stall converter but if I gotta so what.

Im sure I left something out... any Ideas on a cam?
 

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.215 Duration @.050 and .500 lift is what i would go with. Talks to you some at idle, but still has good low RPM power. works with stock TC, no vac problems. Have fount that stick to have good daily driver street manners..and it will love the heads and intake you already have.. I built a 62 Chevy PU a few years back with that same combo (different brand heads..but same specs)..
 

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Hello 'E',

What city you near? Ours off to right --->

You don't have 1.94" exhaust valves... that's another intake valve size... likely have 1.60" exhaust valves... You might have 1.94" intake valves... need to verify...

You prolly won't be able to run 10.5:1 and iron heads on today's pump gas only... without pinging... likely need an ounce or two of kerosene or other octane booster per tank of Premium gas... You may be able to avoid the octane booster by going a little bigger cam than ShopTruck recommended and installing it 4 degrees retarded on the timing chain set and carefully tailoring the ignition advance curve... Say a 224/234 (~425-450 HP) or 234/244 (~450-475 HP) cam... bigger cams get harder to live with in a vehicle driven much...

Your .030" overbored SBC 350 block and 3.75" stroke crank from a SBC '400' is what we all call a SBC 383" engine..

If starting from scratch nowadays, most of us would have used flat top pistons and a smaller combustion chamber to avoid the flamefront blocking effects of a "popup"/domed piston... but it will run OK as is...

I'd suggest about a 2500 stall custom converter... say from Hughes, Coan, or Freak Show...

The cc dome of your pistons and head gasket thickness and deck height of pistons would help in computing compression ratio...

Flat tappet cam/lifters start at about $100/set... roller cam/lifters about $600/set... unless have OEM block already made for OEM roller lifters... What did you have in mind?
.
 

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It's going to take a fair amount of cam to handle your compression that's a bit high for pump gas. The battle will be having a cam that will handle your power brakes and the compression.

You're going to need plenty of cooling system and fresh air flow into the engine bay when cruising. Hot intake temps are not going to be your friend. The Air Gap intake will help. Hopefully your machine shop set you up with a quench distance on the .040"ish area.
 

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Find out what Dart heads you have? Out of the box they do not flow much but do respond very well to porting. If the truck is going to tow anything at anytime then 9 1/4:1 cr is all you want. You should "measure" exactly how far down the hole the pistons are at TDC. Measure combustion chamber volume. Tell us the exact compressed thickness of the head gaskets.
This is an early step in the blue printing process. (expect at least 3 or 4 test assemblies before final assembly)
You need to hand fit each piston, make sure block is squared and properly decked. Align hone if needed. Reciprocating parts should be balanced.750 cfm carb is adequate. Proper sized headers and exhaust is required. Good multi spark ignition system(with out points) is required.

When you have these details then choose a camshaft? The flat tappet hydraulic cam would not be on my list at all. For a mild engine I would use a hydraulic roller or pressure fed solid flat tappet. I would choose to tune the engine to make peak horse power around 5800 rpm for a hot truck. I would be looking for 430 pounds plus of torque.

for now a turbo 350 auto will work.
 

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Hello!
You can call me E for now i guess,

Im new to forums, I read them often but i never join to post anything because Im usually researching a different car and problem each time. Mostly I just harvest the bits and pieces i need to answer my query and leave the rest behind as I find that most of the time the question was asked wrong in the first place and or the thread turns into bickering over tire shine brand preference.
I have not noticed that to be the case in the threads I have read on your site. Thank you.



I joined because I am building myself a hot rod truck to go raise hell with on the weekends.
I think that I would benefit greatly from some of y'all s advice on certain matters if I had the opportunity to ask you, as well as help answer some questions about problems that you may be having with your vehicles.

About myself

I have over 25 consecutive years in the automotive trade as a tech and shop manager . I own my own shop in here in New England now for the past 7 years where we do from major repairs to maintenance on pretty much anything up to say a 1 ton truck.

Typically I do not get to mess around with old small blocks and classic cars as there is minimal demand out here in the trenches...



However, when asked ,most of the time I refuse to work on other peoples hot rods. (and I use that term loosely)

As far as the work that comes thru my shop goes I am simply more interested in production work on late model vehicles.

The old car projects take forever and are in constant need of attention because every 40 or 50 year old bolt has been molested over and over by god knows how many.And it gets more expensive than anybody is ever prepared for. Myself included.

I believe that having and driving something old and cool should be a labor of love and you do not get the cred if you have to pay people to work on it for you.
So I bought a nice 68 GMC truck from somewhere way south of here and ripped it apart. This looks like the second time for the body. The Crap 305 covered in auto zone parts got lost at sea so I am building this truck a proper engine.



So, regarding my trucks soon to be engine, a SB350.... I am currently lost scratching my head feeling overwhelmed in the camshaft aisle.
I have a lot of specs and sizes and ratios and stroke and torque converter and even tire size to consider when selecting a cam. Most of this information I have.

Master certified tech? Yes. Performance Engine Builder? No.
could somebody please help me get the ball rolling here.

Thanks E
For a performance build you need to coordinate the cam with compression. This falls hard of piston and head selection. The cam will dictate the compression ratio through the Dynamic Compression Ratio calculations these are available on the web. The compression ratio will dictate the combustion chamber volume along with the piston's contribution to chamber volume, the deck clearance, and gasket thickness. the big impactor from the cam is the intake valve closing point.

Bogie
 

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Those dome pistons are your enemy. Like someone above said, you need a big cam to work with the high static compression, but a moderate cam to make good vacuum and decent street manners. In either case, high octane gas will be your friend, as will total spark advance on the conservative side.

If you are stuck with those pistons, I'd probably run a cam in the 230 range with a wide LSA, such as 112-114, to reduce effective compression. Keep in mind that small block cam RPM ranges specified in the catalogs are typically for a 350. For example, a cam listed as having a 2000-5000 RPM range will probably be closer to 1700-4700 RPM in a 383. And a 224/230 cam in a 350, will work similarly to a 230/236 cam in a 383.

Is the 383 rotating assembly balanced? That's a must, and it needs to be done with the damper and flywheel/flexplate bolted to the crank.
 
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