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  #16 (permalink)  
Old 06-27-2004, 08:53 AM
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The stock bore size for a 400 is 4.125 or 4 1/8. Unless there is excessive wear .030 normally cleans up the wear. Not all pistons are available in .020 and sometime .020 over doesn't completely clean up all wear. Keep in mind that when you bore and hone to .020 you're only taking away .010 of metal. Let your machinist take a look at your block before you order your pistons if in doubt what size to bore your block to. It's not a bad idea to have the block hot tanked, jet washed, or baked and blasted before you order any parts. That way you can really check the block out good before buy pistons only to find that you have a cracked block.

As for what engine size is going to make power easy with any thing 350 and over it's not hard at all to make more power than the back end of your car can deal with. It going to come down to what you want to build. As for fiction the longer stroke motor is going to have more friction than a short stroke motor. The two biggest sources of friction is the camshaft and the rings. The longer stroke motor slides the rings farther for the same rpm than a short stroke motor of the same cubic inches. This also causes the piston speed to be higher for the same rpm and the G loads on the pistons will be higher. Installing 5.7 "long rods from a 350 instead of the 5.56" 400 rods will help reduce the piston stresses. Of course your pistons will need to have the correct compression height for 5.7 rods. Such piston are not hard to find. With the 5.7" rods you'll have grind on the heads of a couple of rod bolts or use aftermarket rods to keep the cam lobes from hitting the rod bolts. Make sure you get a 400 oil pump drive shaft, they're different from the 350 also.
There are several aftermarket cast iron heads on the market. Aftermarket heads should last you a lifetime for your application whether you use iron or aluminum. Aluminum heads are better for drawing heat out of the motor which helps stop detenation.
Cryo soaking parts is ok but there are a lot shops doing it that are doing more harm than good. Cryo is just another form of heat treating. There's a lot more to it than just dunking parts in liquid nitrogen. The shop must have proceeduress for controlling the rate of change of temps. As with any form of heat treating parts can be warped or made too brittle if done wrong.
The oil cooler is not a bad thing but is complete overkill for your application. The air gap manifold will be useable once the motor warms up in cool weather but in cold weather it's going to be a problem unless you rig up some short carb heat like a stock air cleaner. It is a rather tall manifold so make sur that you have hood clearence.
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  #17 (permalink)  
Old 06-27-2004, 12:27 PM
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Quote:
Originally posted by Croz
If i remember correctly, a 400SBC is less reliable than a good 350SBC. They also don't make a 4 bolt main 400SBC to my knowledge. Other than that, I am still a little fuzzy as to what it is you want, and what you are asking.
It's my understanding that they're the same size Block,accept for the Cylinder Bore's.

Thats why you can drop a 400 SBC Crank into the bottom of a 350 SBC,
& make a 383 Stroker.

If they're the same size as a 350,& you'r going to bore,& stroke the 350 how could the 400 be "Less Reliable"?

Don't know if the're making any now a days "Yet",
but GM defiantly made 4 BM 400 SBC's,mainly back in the 70's.

Here are the Casting #'s for all the old 400 SBC's

#330817 72-80' 2BM

#3951509 70-71' 4BM

#3951509 73-80' 2BM

#3951511 70-73' 4BM

#3030817 73-76' 2BM

As i said earlier on this thread,
"I'll know exactly what I'm doing,before I jump".

Share the wealth,if you know anyone who needs these #'s.

Although I don't see your point.It's also my understanding that the 2BM 400 SBC's are more desirable because they have more Integrity.

As far as what I'm looking for,I tried to explain it as best I could in "all" the above posts.

If there's something in particular I forgot to ask,or make mention of let me know,& I'll try to cover it.

tresi

I'll get back to you after I've had time to digest it all.
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  #18 (permalink)  
Old 06-27-2004, 06:28 PM
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Quote:
It's my understanding that they're the same size Block,accept for the Cylinder Bore's.
Quote:
If they're the same size as a 350,& you'r going to bore,& stroke the 350 how could the 400 be "Less Reliable"?
you answered your own question...

As far as the fuzzy topic... the first post sounded likey ou simply wanted to know whether a high revving engine would go better with a manual compared to a high torque motor. Now it sounds more like you want to know how to build an engine that will last the longest, disregaurding torque and horsepower figures..... Then at another point in the thread it sounded like you wanted to know how to build the perfect engine (i.e. runs cool, high horsepower, long life...).
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Old 06-27-2004, 07:44 PM
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tresi

Thanks for the Spec,I'll get ahold of a set of Calipers as soon as I can.I appreciate the Sug to get the Block Tanked as well.I was going to clean it up myself,but I called my local Nappa & they said they'd do it for $45.00.

As grimy as this thing is I CAN DEFIANTLY LIVE WITH THAT.
Not to mention if it is cracked,I will know sooner,& be able to return it to the Yard in a timely manner.

As soon as I find a GOOD Mechanist,& the other work is done I'll find out how much IT HAS TO have taken out of it.I really would like to keep the Boring down to a minimum.

As for the Cryoing,I'm Hip.I've been following it for years now,& I know where your coming from.I'm not going to have some JOKER dip it in Liquid Nitro,or chuck a Bunck of Dry Ice on it.

I'm going to send it to a Professional,where they slowly lower the temperature a degree at a time until it reaches -300,then bring it back up in the same manner.

I have found a GOOD Reputable Cryo Company in Central Illinois,(not to far from here) where I can drop all the GOODIES off,(including the block) & pick them back up again the same week.So I won't have to pay $150.00,(or more) to have it shipped,& then again to receive it back.

Saving $300.00 or more while seeing a little more of the Countryside sounds pretty,(insert curse word here) GOOD to me.

I'd prefer to Rebuild the 400.As long as the one I have access to proves to be a Good solid Block then I'll stick with it.If not then my next choice will more than likely be a 383 Stroker,so I can retain the BIG Crankshaft etc...

Say how is it you can use 350 Rods with a 400 crank???

Or did you simply mean 350 "Length" Rods made for a 400 rank?
Anyway I appreciate the info on the internals.

On the Heads,if they are going to last as long then I won't through Aluminum out the window entirely.Rather I'll se what I can get ahold of for how much.If I'm not at the end of my Monetary Rope by the time all of the other parts,& services are bought,& paid for then I'll see what I can afford to swing on the Heads,or leave them on hold till Income Tax time.

Either way what do you think would be GOOD Heads to run with this Motor,(bearing the Air-Gap in mind)? Every way would be GREAT,(old cast iron,& new after market aluminum,& cast) that way I could simply keep an eye out for all three,& Snab-Up something GOOD,& not Miss Out on a GOOD Deal if one happened to come along.

If it's going to be both to much of a Hassle,& Expense I'll go with something other than the Air-Gap.If not then I'd prefer to stick with it.What exactly are you referring to when you say "Short Carb Heat",& what are all my options to achieve it?

Possibly something I can run in Cold Weather only,& leave off the rest of the time?

P.S. On the Oil Cooler being "Overkill" are you referring to the Transmission,
or Engine Oil model,or both?



Croz

I was looking for input.Hopefully from people who had experience in
Building SBC's Specifically for the purpose of "Mating" them to Manual Transmissions.

I was not leaning toward anything as far as Torque,RPM's or even Horsepower is concerned.In fact if you Review all of my posts in this
particular Thread I believe this post is the first time I have made Mention of Horsepower at all,& I'm still not asking about it.

Someone has made several responses in order to help me better understand
"how" to reach my Goal,I have mearly adjusted my responses to his,
so that I can.

I never claimed to have Knowledge of "The Perfect Motor" either.
Nor am I purposefully in search of it.I simply need to build an Engine that best fofills my needs.If it just so happens to be the "Perfect Motor",or the closest thing to it when it's finished,then so be it.

My main goals remain my main goals,irregardless of what it takes to accomplish them.As long as they are fofilled I am content.Of course I have some Preferences,thats simply a part of being Human,& even moreso an individual.

As opposed to a Dead fish with a weak Handshake that simply follows the pack wherever it may roam.

If you can understand where I am coming from as far what I need to get out of an Engine for this particular application,& you have some valuable insights,
or experience in accomplishing the same Goal,then I would like to hear it.

If you don't know where I'm coming from by now,then unfortunately we are more than likely to "opposite" to be able to communicate effectively with each other.

As far as being "Fuzzy" I try to shave as often as I can,but doing so everyday
breaks me out.Even still when I am a bit "Fuzzy" I remain quite Handsome none the less.
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  #20 (permalink)  
Old 07-01-2004, 02:53 PM
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SBC 400 vs. 350

My father retired after 30+ years at the GM Tech Center. During my years at home, I learned a few things about the SBC engine. The blocks are basically the same from the 265 all the way up to the 400. The original 400 of the early 70's did have a reliabilty problem. The increase in bore decreased the thickness of the cylinder walls to the point they would warp. This was later "corrected" by closing off some of the water cooling areas between the cylinders. This caused slight overheating problems, but kept the engine more realiable. Be certain to get a later year block or boring it will give you even thinner cylinder walls and warping.

If you want reliabilty, go with the 350 or 383 stroker motor. You can easily get 300+ HP and 300+ ft. lbs. of torque out of either and still have reliability. One thing to avoid is....Do not use a nylon coated aluminum cam timing gear. The nylon gets brittle and break off. These were original equipment on SBC's up to at least the mid-70's and maybe further. Get an all metal gear.
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  #21 (permalink)  
Old 07-01-2004, 09:23 PM
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mytwopals

Thanks for the Info.It's always good to hear from someone who KNOWS what there talking about,& even better to gain applicable knowledge.

So essentially the ONLY difference between a 305,& a 400 is cylinder bore size?

I knew it was true of the 350,but I had never heard that it trickled down to the smaller CID's.

Is there any difference in the lower section of the Blocks?
In other words,would a 400 crank fit into a 305 Block,without modification?

If not what are ALL the other differences between the Blocks other than Cylinder Bore Diameter?

So if "The blocks are basically the same from the 265 all the way up to the 400" wouldn't a 305 be just as dependable as a 350?
If not,then why not?

Since we're on the subject of all the blocks being basically the same,
do you happen to know,(or can you possibly ask your dad) if there was a time when they were changed to being different from one another.

Or do ALL of the model years of SBC's share the same Basic Block?
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  #22 (permalink)  
Old 07-02-2004, 11:52 AM
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The bore is one of the differences between a 305 and 350. The crankshaft is also different, which provides for the longer stroke of the 350 vs. the 305. Another difference would be 4-bolt vs. 2-bolt main bearing caps. I don't believe the 305 was ever built with a 4-bolt main. The 350 was built with either 2-bolt or 4-bolt mains. A 4-bolt main block will generally handle higher RPM's without falling apart, providing the rods, pistons, etc. will also handle the higher RPM's.

Cranks, heads, cams, and intakes are interchangeable with other SBC engines. This is one of the reasons they're so popular.

As for reliability, the 305 properly built should be as reliable as a 350. But the 305 being a 2-bolt main block, will not handle large amounts of horsepower as reliably as the 350 4-bolt block. Remember also, there's no substitute for raw cubic inches.

The 400 crank should fit the 305, but you may need to use shorter connecting rods to avoid popping the pistons out the top of the block. For instance a 383 stroker motor is simply a 350 with a 400 crank in it to provide the longer stroke.

If I were building it myself, I'd go with a 350 4-bolt main block. I'd stick to 9.5 to 1 or 10.0 to 1 pistons. You'll still be able to run on normal pump gas. Stick with the 350 crank, it'll be fine. The cam selection is really where you'll decide torque vs. HP. My personal opinion would be to select a cam, where the horsepower range began about 2500 RPM through about 4000 RPM. This would be considered a streetable cam. But with a manual transmission, you could go a bit wilder with the cam. Top it off with an aluminum single plane manifold and the 650-700 CFM carb of your choice and a GM HEI distributor set up. With this setup, you'd be around 300HP with good torque throughout the RPM range.
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  #23 (permalink)  
Old 07-02-2004, 04:53 PM
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Quote:
Originally posted by Stick'n It
mytwopals

Thanks for the Info.It's always good to hear from someone who KNOWS what there talking about,& even better to gain applicable knowledge.

So essentially the ONLY difference between a 305,& a 400 is cylinder bore size?

I knew it was true of the 350,but I had never heard that it trickled down to the smaller CID's.

Is there any difference in the lower section of the Blocks?
In other words,would a 400 crank fit into a 305 Block,without modification?

If not what are ALL the other differences between the Blocks other than Cylinder Bore Diameter?

So if "The blocks are basically the same from the 265 all the way up to the 400" wouldn't a 305 be just as dependable as a 350?
If not,then why not?

Since we're on the subject of all the blocks being basically the same,
do you happen to know,(or can you possibly ask your dad) if there was a time when they were changed to being different from one another.

Or do ALL of the model years of SBC's share the same Basic Block?
With out modifications a 400 crank will only fit into a 400. The 400 had larger diameter main bearings.
Some 305's are just as reliable as 350's, I've seen some go as long as 300,000 miles with no internal repairs.
While all small blocks share many dimensions they are not all the same. Some blocks have more nickel and tin in the iron. Some blocks like the 307's and early 305's had the crappiest iron I've ever seen in an engine block. There are dozens of other minor variations over the years. The blocks with the cast in 010 and 020 under the timing cover are the blocks with more tin and nickel.

Last edited by tresi; 07-02-2004 at 05:14 PM.
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  #24 (permalink)  
Old 07-03-2004, 03:58 PM
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Well Guys,

While I appreciate all of you who have helped out,
(instead of just mouthing off) this is still allot to wade through.

To much to research,& KEEP in Mind,
(my three children,wife,animals,land,home etc...
command most of my attention at the present).

So I will go another route.

Once again,Thank You.
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