what 5.3 heads are the good ones for the ls1

[Formula Z]

i have a friend with a 99 5.3 motor that is sitting and he offered it to me pretty cheap. im mostly interested in the heads if they are the ones we can do some work to and have better then the stock ls1 heads. i havent been down there to see the casting numbers but if someone can tell me the numbers maybe i can just call, lol. thanks

[sman]

Pretty sure there all the same, they flow worse than the ls1 heads, but have a smaller chamber so they raise the compression ratio. But with a valve upgrade and some porting they are better than the ls1 heads, hence the reason the aftermarket companies use them.

[Formula Z]

so with that and a good cam, it could be better??? thanks, just an option for a winter project

[mikek18]

A good winter project would be to get a 6 speed. lol

[Formula Z]

if the funds were there, it would be a done deal. im kinda strapped with these two leases i have, which will both be going back soon, then i can do what i want

[sman]

After a valve job and some porting they are definitely better than ls1 heads. Thats why everyone sells versions of 5.3 heads.

[DETROITMUSCLE]

I have 5.3s that flow very well and I like the added compression for a N/A motor.

[Formula Z]

so it doesnt matter the casting number

[98ultraz]

I have PRC stage 2.5 5.3l heads and work really well

[sman]

Not to my knowledge, because all 5.3 heads should be the higher compression ratio. And thats why people want them.

[Formula Z]

cool man thanks

[sman]

No prob.

[Formula Z]

ok got the whole motor, now just to price out the porting and valve job. any ideas on cost for this kind of work and someone who can do it?? thanks

[sman]

Light ports start around 450 in my area. I was told about a thousand to really work them over, valve job, and upgrade to some bigger valves. (Bigger valves supposedly make all the difference in these.)

[Formula Z]

well the 5.3 was delivered yesterday, tried mounting it to my engine stand but it didnt look like that would be safe. so its on the floor. i need a new engine stand. anyways its here and now to find some prices and cash.