[Greg T]

I finally identified this SBC I have but am kinda wondering what someone did. The block is a 3970010 . The engine vin is V1130TKB. Now, this resolves to a 76 or 79 350 conventional cab truck, 165 hp 4 bbl. BUT, the engine is a rebuild from a parts store. So, I check the heads and they are 416 which are 80 to 86 305 cid with 1.84/1.50 valves and 58cc chambers. Thinking something is funny about this I do a compresssion test and find 175 cranking pressure. Now, being a stockish rebuilt, isnt this compression a little high? Would anyone have a close guess as to the static CR?

See, I want to build some power into this thing but with 58cc heads already on there I'm wondering what the heck pistons could be in this thing. Any guesses based on the chamber size and cranking pressure?

[SSedan64]

Originally Posted by Greg T

I finally identified this SBC I have but am kinda wondering what someone did. The block is a 3970010 . The engine vin is V1130TKB. Now, this resolves to a 76 or 79 350 conventional cab truck, 165 hp 4 bbl. BUT, the engine is a rebuild from a parts store. So, I check the heads and they are 416 which are 80 to 86 305 cid with 1.84/1.50 valves and 58cc chambers. Thinking something is funny about this I do a compresssion test and find 175 cranking pressure. Now, being a stockish rebuilt, isnt this compression a little high? Would anyone have a close guess as to the static CR?

See, I want to build some power into this thing but with 58cc heads already on there I'm wondering what the heck pistons could be in this thing. Any guesses based on the chamber size and cranking pressure?

That's odd to have 305 heads, I guess they used what was on hand.
Assuming 4.03"Bore, .025" piston deck height, 16cc dish piston, 58cc heads, .040" gasket = 9.31 CR

[curtis73]

Originally Posted by Greg T

BUT, the engine is a rebuild from a parts store.

You just answered your own question. They throw together s#!t that shouldn't be on a pizza. 99% of their business is people who don't know anything.... let me rephrase... people who know less than the parts store employees, which usually means next to nothing

They build replacment engines with salvaged parts and hope that nobody notices that one head is 76cc and the other is 64cc. Start really looking at generic reman engines and you might be shocked.

[Greg T]

Oh, I'm well aware of what comes out of those places. But I didnt buy this from a store. It was in a cube van, virtually no miles and cheap. runs perfectly. I just want to put some power in it and was kinda shocked to see 58cc heads already on there. so, basically, I have no place to go for 10.3:1 static cr.

That's odd to have 305 heads, I guess they used what was on hand.
Assuming 4.03"Bore, .025" piston deck height, 16cc dish piston, 58cc heads, .040" gasket = 9.31 CR

9.31 sounds kinda high for a parts store rebuild. I was assuming they pu them at about 8.5 or so. 9.3 aint all that bad because I can always use thinner gaskets and maybe a 52cc chamber to hit my 10.3 mark. I havent looked, but I'm hoping that AFR can supply the chamber size I would need.

[sam-missle]

if the engine has rebuilder pistons in it, which is likely. the pistons would be .045 down.

sam-missle

[Greg T]

Originally Posted by sam-missle

if the engine has rebuilder pistons in it, which is likely. the pistons would be .045 down.

sam-missle

I thought of that earlier, but then, 8.5 cr wouldnt yield a 175 psi cranking pressure.