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Discussion Starter #1
Mortec shows that the same block number is used for the three engines.

3970010....302.....69....4...Z-28 Camaro
3970010....327.....69....2...Trucks and industrial
3970010....350...69-80...2 or 4

If I can get one of these blocks which one would be best to build and will have more HP.
 

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Blocks don't make horsepower. The stuff you put in them and on them makes power. The only issues with a block are fit, originality, size, and durability. You can make any four inch bore block into a 302, 327, 350, or 377 depending what crankshaft you use. If you can find an original DZ 302 block please sell it to someone with a Camaro who can make good use of it. Any four inch four bolt main block will make a strong foundation for a high power engine and you can always put splayed caps on a two bolt block if you need the added strength.

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'69 RS Camaro
355 5-speed 4.11
 

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not to be a D*ck but i think you mean, 302, 327, 350 or 383.
A 377 is a destroked 400 block.

Personally if i was starting from scatch and had to buy a block, i'd be looking for a 400 block that's usuable and using a 3.75" stroke crank in it.
If the crank needed to be ground i'd have it offset ground also (stroked even more).
 

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4 X 4 X 3.75 X .7854 X 8 = ? I'll let you do the math.

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'69 RS Camaro
355 5-speed 4.11
 

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Well said 1 2 Run. Your exactly right about the sizes 302, 327, 350, 377.

CNC - a 4.030" block can be used to make a 306, 331, 355, or 383. A 4.060" bore can be used to make a 310, 336, 360, or a 388.
 

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Has anybody out here built a long rod 302+.030 (306)? I need to turn my 331 small journal crank again and I'm considering picking up a 283 crank for it. I noticed that the 383 pistons designed for the 5.7 rods have a comp height of 1.425". With a 3" stroke and a 6" rod it should work out to .075" quench if my block hasn't already been decked, which I believe it has since the pad stampings are gone. I think I can deck it enough to get my quench down to .015-.030 without any problems. If I ran Speed Pro hypers H635P with .240' domes I'd get 12.6:1 with 64cc chambers and if it proved too much 76cc heads drop it to 11:1. I know the later wouldn't be a problem with the 6 " rod, especially if I am careful on my cam selection. Airflow has already proven you can run 11:1 with a 6" rod on pump gas today. Any thoughts?

[This message has been edited by SY1 (edited 10-24-2002).]
 

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I dont know much about building engines but I remember very well reading at pop. hot rod. about 5 years ago that you can even have regular 350 engine run on pump gas with 11:1 comp. if you have smaller cc heads(55cc) with better flame propogation like flat top pistons. thay achived this in the article angle cutting production 64cc heads.
 

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SY1, that's a good idea. You could also have that 283 crank offset ground to eat up some of that extra deck height. Might be easier than decking the block another .040" or more. I think you would gain an extra 3 or 4 cubes out of it if you offset .020".

You might also look for a short 350 piston with a compression height of about 1.50". I found that compression heights vary a little from mfr to mfr - don't they normally run about 1.55"?

You could always mill a flat top 350 piston down a little, but then you would need a very small cylinder head to get the kind of compression you are looking for.

I think KB's tend to be on the taller side - my new SRP flat tops were .009" shorter than my old -12cc dish KB's.
 

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Eric,
Good thought about offset grinding the crank. It certainly wouldn't hurt to pick up any extra cubes on the little motor. I'd seen a couple of NOS 283 standard cranks still crated, if I was lucky enough to get one of those it would be nice to not disturb the tuftrided bearing surfaces. But if I get one I need to grind offsetting the throw is something I'll consider.

I believe the 400 pistons are 1.56' comp heights and 327 are 1.675, 302 are 1.80 and 383 for the 5.7 rod are 1.425. I'm not sure about 350 pistons, I haven't built a 350 since I blew my last couple of them in 1980. I've stuck with shorter stroke motors since then, just personal preference. I know the figures for the comp heights ar from Chevy and they do vary some. The thing I think I'll do is put it together and see how it mics out and decide what needs to be done. I thought about milling the pistons, but it's a little tricky unless you're running flat tops.

I'd wanted to build a short stroke, long rod 400, but after another round of bad news from our company, I've decided to just work with the small journal block I've got on the stand right now.

Dave
 
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