decent compression?
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Joined: Jul 2002
Posts: 519
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From: marlborough/dartmouth, MA
Car: 1988 IROC-Z
Engine: LB9
Transmission: 700R4
decent compression?
im in the process of planning a future engine...i was checkin out a L31 and L98 shortblock from SDPC and theyve got 9.0:1 and 9.1:1 respectively...this is lower than stock right? if im lookin for a 400 hp motor, is this gonna be high enough (decent) compression? ...how could i raise compression without changing pistons or havin it decked, etc?...what about gasket-wise? i dunno...thanks guys
oh, those CR figures are with a 64cc head
oh, those CR figures are with a 64cc head
Joined: Jul 2003
Posts: 10,532
Likes: 204
From: NYC / Jersey
Car: 1990 Trans Am GTA
Engine: Turbo 305 w/MS2
Transmission: 700R4
Re: decent compression?
Originally posted by IROCZ88x
If im lookin for a 400 hp motor, is this gonna be high enough (decent) compression? ...how could i raise compression without changing pistons or havin it decked, etc?
If im lookin for a 400 hp motor, is this gonna be high enough (decent) compression? ...how could i raise compression without changing pistons or havin it decked, etc?
As for hitting 400HP with 9.1 compression, this should be relatively easy.... provided you choose the right valvetrain. We dyno'ed a stock L98 (stock block, heads ported/three angle valve job).... with a Crane roller cam (Duration @ .050" 222/230 Lift .509"/.522"), lifters and rockers (1.6 ratio).
We got 406HP at 5300RPM...
Forgot to add.... our L98 stroke, bore, and compression level was completely stock.
(I credit our CARB/Fuel set up for the above HP quote though)....
Last edited by Street Lethal; Sep 15, 2003 at 08:02 PM.
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