03 heads

sting5841 · September 3, 2003

has anyone put stock LS1 or LS6 heads on there 5.3L if so what kind of difference did you see?

04GMC8100HD · September 3, 2003

I haven't seen that, but I have seen a guy port a set of 4.8 heads and put them on a 02 TA along with a cam and make 430 rwhp.

Randy

ShortCrew · September 3, 2003

Unless there is some major change for 2003, you will lose power if you put LS1 heads on your 5.3L. The 5.7L heads are identical to the 5.3L except they have larger combustion chambers, which will lower your compression.

On my 2000 Camaro SS, I installed a set of ported 5.3L heads because they add compression.

CMNTMXR81 · September 3, 2003

Yea, but if you're planning on running boost (bigger levels) that is an advantage. However, if you plan on going N/A, a larger combustion chamber will reduce your compression ratio, therefore not netting any gains in power.

MCourson · September 7, 2003

Yea, but if you're planning on running boost (bigger levels) that is an advantage. However, if you plan on going N/A, a larger combustion chamber will reduce your compression ratio, therefore not netting any gains in power.

Im not too sure but I have always heard that if you were going to build a forced induction motor you would want a lower compression ratio. How true is this?

01Burb · September 7, 2003

Generally true. But only if you start to turn up the boost. Obviously most bolt-on superchargers don't require you to change out your hads or pistons but if you lower the CR you can run more boost - generally.

MiSdIrEcTeD_1 · September 7, 2003

I haven't seen that, but I have seen a guy port a set of 4.8 heads and put them on a 02 TA along with a cam and make 430 rwhp.

Randy

Yup, thats one of Arlington Motorsports Cars, and sweet at that.

For the record I cant think of A time that Ive heard of anyone swapping for LS1 heads... Not saying it cant be done, just havent heard of it happening... Ill do some research.

ktmrider · September 22, 2003

I just posted a similar question. All the above feedback is exactly the same info I have received on LS1Tech. People DO go to the LS1 heads mainly because you can get them cheap and improve the flow considerably over the stock 5.3/LM7 heads. The stock heads have much smaller valves compared to the LS1. Reworking the stock heads is much more expensive compared to finding the LS1/LS6 heads and milling them down to get the CR back. It is very true that the LS1 heads have a larger combustion chamber, thus lowering the CR when doing a straight install on a 5.3/4.8L. Ideal if you are going to run some type of forced induction but bad for NA applications.

See my post or I'll update as info comes or the work is finished.