mr silverado

for a 2000 silverado 1500 5.3 would it be better to port out my heads or buy ls1 heads and whats the diff?

holyspatulaboy

dont go advertiseing you will trade your heads for ls1 heads youll probably get a response quicker than expected, people are actually trading in their ls1 heads for lm7 (5.3) becasue they give you higher compression than the LS1 heads, and they have the same flow just the chamber is smaller by a few mm which = more compression, keep heads and swap for taller cam, better springs, and lighter valves. you will keep your compression higher with the 5.3 heads and get good gains from the adds.

actually this is a copy past from another froum from another site,

The reason so many LS1 cars run 5.3L heads is not becasue they flow better. Stock for stock LM7 heads flow nearly identical to LS1 heads. It's for the smaller combustion chambers to raise compression. The smaller chamber also means that the head can be ported more without needing to mill them down to regain compression. The L33 5.3L runs the same heads as a LS6, but without the lightweight valves which definately flow better than LS1 heads.

its easier explaining this way...lol. to prevent confusion the LM7 and L33 are both 5.3

mr silverado

so you r saying that it would be better to port it right.

holyspatulaboy

yes, i would kep the 5.3 heads, but i would try and find the aluminum ones off the L33 if possible if not stick with the stock and port.

mr silverado

and do you know how big of a diff will i feel when i get it ported?

holyspatulaboy

that i cannot say