5.3L build 862 vs 317 heads (compression)??
#42
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Hey I never was much a turbo fan but mostly because of the disasters if improperly installed but i was looking at twin turbo for my 5.3L 2000 chevy silverado 4x4 ls and a cam upgrade possibly new heads. I have headers and flow masters for exhaust and a cold air intake from Is3, monitored with hypertech max what would be a good compression if I bore it out to accommodate the twin turbo and a lil spray
#43
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I'm looking to build a 2002 5.3l chevy. I'm going to carborate it and put twin 76mm turbos on it. Bottom end is stock. What heads are best for that? Apparently 317 heads are too low compression? Will the stock heads shaved 30 thousandths work fine? It has 11.1 compression now. How much boost can I run on pump 93 non ethanol?
#44
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Originally Posted by 1994silverado
I'm looking to build a 2002 5.3l chevy. I'm going to carborate it and put twin 76mm turbos on it. Bottom end is stock. What heads are best for that? Apparently 317 heads are too low compression? Will the stock heads shaved 30 thousandths work fine? It has 11.1 compression now. How much boost can I run on pump 93 non ethanol?
#45
#47
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I did some quick calculations and a LM7 with flat top pistons, cometic .040" MLS head gaskets and 317's w/ a 72cc chamber should net a 9.52:1 compression ratio.
Down slightly from 9.8:1 on a LS1 w/ the same 317's.
That reduction doesn't seem too bad at all for a street car and would allow a touch more boost.
Thoughts?
Down slightly from 9.8:1 on a LS1 w/ the same 317's.
That reduction doesn't seem too bad at all for a street car and would allow a touch more boost.
Thoughts?
#48
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I did some quick calculations and a LM7 with flat top pistons, cometic .040" MLS head gaskets and 317's w/ a 72cc chamber should net a 9.52:1 compression ratio.
Down slightly from 9.8:1 on a LS1 w/ the same 317's.
That reduction doesn't seem too bad at all for a street car and would allow a touch more boost.
Thoughts?
Down slightly from 9.8:1 on a LS1 w/ the same 317's.
That reduction doesn't seem too bad at all for a street car and would allow a touch more boost.
Thoughts?
If a flat top LC9 with 64.4cc heads is 9.6:1. Add 6.5ccs with the 317 heads and subtract a cc or so for the .010 thinner head gasket. You'd around 9:1. If you mill the 317's .030 and you'd be in better shape. I just milled a set and it cost me $75.
#49
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Originally Posted by The ******
I did some quick calculations and a LM7 with flat top pistons, cometic .040" MLS head gaskets and 317's w/ a 72cc chamber should net a 9.52:1 compression ratio.
Down slightly from 9.8:1 on a LS1 w/ the same 317's.
That reduction doesn't seem too bad at all for a street car and would allow a touch more boost.
Thoughts?
Down slightly from 9.8:1 on a LS1 w/ the same 317's.
That reduction doesn't seem too bad at all for a street car and would allow a touch more boost.
Thoughts?
#51
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#52
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I think you did your quick math incorrectly. Compression will be lower I'd think.
If a flat top LC9 with 64.4cc heads is 9.6:1. Add 6.5ccs with the 317 heads and subtract a cc or so for the .010 thinner head gasket. You'd around 9:1. If you mill the 317's .030 and you'd be in better shape. I just milled a set and it cost me $75.
If a flat top LC9 with 64.4cc heads is 9.6:1. Add 6.5ccs with the 317 heads and subtract a cc or so for the .010 thinner head gasket. You'd around 9:1. If you mill the 317's .030 and you'd be in better shape. I just milled a set and it cost me $75.
Add a .040 head gasket and 72cc heads I get 9.5:1 compression per the calculator I'm using.
What am I missing?