Hawaiian_Built

iTrader: (15)

I'm getting ready to put my motor together, but I want to make sure I'll be good on 91 octane cause we dont have 93 here in vegas. I picked up a set of PRC stg 2.5 5.3L heads for my LQ9 and now am worried my comp may be a bit high. The cam specs I will be using is 224/230 .610 .605 11+2. I've read anywhere from 10.9:1 to about 12:1. I was planning on using Factory GM 5-layer MLS head gasket, 051 in. Compressed Thickness, 4.080" bore.

What will my compression be?
Will this gasket work or should I use something else?

*****Edit****** I just found out that they are 61cc

litle88

iTrader: (20)

What is the combustion chamber size?
What is your exact bore size?

We need that to determine your compression.

Hawaiian_Built

iTrader: (15)

Sorry about that.
61 cc heads
And its stock lq9 shortblock 4.00

litle88

iTrader: (20)

11.14 is what I'm coming up with bud.

http://www.angelfire.com/fl/procrastination/motor.html

Pwebbz28

iTrader: (31)

Ls2 compression is 10.9:1 with a 65cc ls6 head so if you take a cc or 2 off that you are probably looking at a touch over 11:1. for 91 octane that is getting up there but you should be fine if you dont throw a ton of timing at it. Im sure there are plenty of TBSS's running around on 91 octane.

Hawaiian_Built

iTrader: (15)

Found out they are 61cc heads

litle88

iTrader: (20)

You'll be at 11.54 which is nice not bad at all. But I would check your PTV clearances just in case.

Hawaiian_Built

iTrader: (15)

So it would be safe on 91?

OUTLAWZ RACING

iTrader: (9)

Yep just dont get to agressive with timing.

litle88

iTrader: (20)

Yup^^^

Hawaiian_Built

iTrader: (15)

Thanks guys. I will be pressing forward with my build. I really appreciate the info