quick compression question

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Mar 1, 2008 | 12:53 PM

rube1975

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Racer

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From: Springfield MA

quick compression question

Ok stock L98 bottom end with 49cc combustion chamber what is the compression ratio?

Mar 1, 2008 | 01:21 PM

vader86

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From: Athens AL

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This is on your 89?

Mar 1, 2008 | 04:17 PM

rube1975

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Racer

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From: Springfield MA

yep

Mar 1, 2008 | 05:43 PM

CFI-EFI

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From: The Top of Utah

Quote:

Originally Posted by rube1975

Ok stock L98 bottom end with 49cc combustion chamber what is the compression ratio?

Combustion chamber in the bottom end? The combustion chamber, being in the head is usually considered to be in the top end. No Corvette L98 has 49 cc, combustion chambers, stock. They are either 76 cc in 1985 and 1986E engines and 58 cc in 1986L through the end of their use in 1991. Besides combustion chamber size, the pistons varied, and there were more than just the two compression ratios that only the head change would account for.

RACE ON!!!

Mar 1, 2008 | 07:04 PM

vader86

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Starting with a 9.5:1, i figure you'd go up about 1-1.5

Mar 1, 2008 | 07:16 PM

mgbss

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From: Mt Pleasant Michigan

It looks like on a 350 ci the difference between a 58cc head and a 49cc head with all things being equal you would gain about 1 point 9.55 with a 58cc to 10.6 with 49cc

Joe

Mar 1, 2008 | 07:43 PM

rube1975

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Racer

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From: Springfield MA

so 10.6:1 with stock bottom end and 49cc heads
now that will work with 93 octane and the right cam
correct???

Mar 1, 2008 | 10:23 PM

vader86

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Quote:

Originally Posted by rube1975

so 10.6:1 with stock bottom end and 49cc heads
now that will work with 93 octane and the right cam
correct???

After the custom chip, sure.

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Mar 2, 2008 | 12:48 AM

cmashark

Burning Brakes

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From: Atoka, TN

what did those heads come from? 305?

Mar 2, 2008 | 02:13 AM

#10

rube1975

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Racer

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From: Springfield MA

DART
49cc but 200 intake runner

Mar 2, 2008 | 12:51 PM

#11

CFI-EFI

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From: The Top of Utah

Quote:

Originally Posted by rube1975

so 10.6:1 with stock bottom end and 49cc heads
now that will work with 93 octane and the right cam
correct???

THAT (above) is what THIS (below) was asking???

Quote:

Originally Posted by rube1975

Ok stock L98 bottom end with 49cc combustion chamber what is the compression ratio?

WOW!!!

RACE ON!!!

Mar 2, 2008 | 04:23 PM

#12

rube1975

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Racer

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Posts: 367

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From: Springfield MA

Quote:

Originally Posted by CFI-EFI

THAT (above) is what THIS (below) was asking???WOW!!!

RACE ON!!!

yep i think its clear srry if you didnt get it

Mar 2, 2008 | 05:01 PM

#13

Curveit

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From: San Antonio Texas

I don't know how far the valves are off the deck with the smaller combustion chamber in these heads... would valve to piston clerance possibly be an issue with your combo? Depending on the lift of your cam too, of course.
P.S. I think 305s have a 58CC chamber.

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