Ls3 top end on LQ4?

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Dec 23, 2020 | 02:54 PM

Vette-byrd

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Ls3 top end on LQ4?

Is this worth while with the lower comp of an LQ4?
car is a weekend toy with manual trans and Texas speed stage 3 cam. Anyone know what the comp ratio would be?
Currently have a sbe LQ4 with stage 3 cam listed above and 862 heads.

Last edited by Vette-byrd; Dec 23, 2020 at 09:13 PM.

Dec 23, 2020 | 08:09 PM

383z

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Yes, it's better than the those heads or any stock cathedrals in my opinion

Dec 23, 2020 | 09:04 PM

G Atsma

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It will be 9.53:1 with stock LS3 heads and LQ4 short block, figuring .052 HG and .00 deck clearance

Dec 23, 2020 | 09:13 PM

Vette-byrd

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Quote:

Originally Posted by G Atsma

It will be 9.53:1 with stock LS3 heads and LQ4 short block, figuring .052 HG and .00 deck clearance

What head gasket is that? I’ve got ls9 head gaskets fwiw.
is milling the ls3 heads an option to get more compression?

Dec 23, 2020 | 09:51 PM

G Atsma

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That is common LS HG thickness. Unless it's .051....

Jan 1, 2021 | 01:51 AM

Vette-byrd

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Any ideas how much power this combo should make?

Jan 1, 2021 | 07:49 AM

BCNUL8R

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Quote:

Originally Posted by Vette-byrd

Any ideas how much power this combo should make?

Probably make bigger peak numbers, but lose response and low end torque.

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Jan 1, 2021 | 04:54 PM

Vette-byrd

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Quote:

Originally Posted by 95wannabe

Here's what mine did with a 222/230 emissions friendly cam. Heads milled only .005" for flatness. Same LS9 hg.

399hp 396 tq?
was that an LQ4 Shortblock?
engine dyno or?

Jan 1, 2021 | 05:38 PM

#10

wannafbody

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If NA, then a smaller chamber head would gain compression.

Jan 1, 2021 | 05:46 PM

#11

RedXray

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Quote:

Originally Posted by Vette-byrd

399hp 396 tq?
was that an LQ4 Shortblock?
engine dyno or?

The chart says "Dynojet" so it's a chassis dyno.

Jan 1, 2021 | 05:56 PM

#12

95wannabe

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Quote:

Originally Posted by Vette-byrd

399hp 396 tq?
was that an LQ4 Shortblock?
engine dyno or?

Yes, everything stock except the cam/springs.
02 sbe LQ4
L92 heads milled .005
LS3 intake with Fast 92mm TB.
Chassis dyno and worth noting it's a 4l60e with small stall thru a 9"

Last edited by 95wannabe; Jan 2, 2021 at 07:58 AM.