Well, i'm lookin into getting some more horsepower N/A. Can't afford getting an S2 head, so I was wondering if I would gain anything if I was to buy a set of stock 5.3s, and have 'em milled 25 though or so?

 

if you mill it .015 i think that put you at 11.1 cr ratio. you don't want much mor thn that.

 

Ok, why is that? Anyone else?

 

11:1 is about the max for 93 octane any more compression and with 93 and your motor will start pinging. I would even watch out with 11:1 if you get a bad tank of gas your are screwed.

 

screwed? how's that? plenty of guys push it far further than that on pump gas, myself being one of them, fireball another, have done .060 on 5.3L heads and made 12.5:1 work w/ pump gas. it all depends on how much you want to mess with it.

 

Would there be any horsepower gains from milling some unported 5.3s?

 

I've gone .040 on mine...93 octane only but running a large cam to bleed off dynamic cyl pressure helps too

 

bad idea. you at least want to have bigger valves put in. the stock intake valve in the 5.3's are very small. like 1.7-8" or somethin. the compression might net you 10-15 RW though.

 

Ive heard its as low as a 8-10 hp gain per point of compression raised. Hardly worth the time or expense.

 

i just got 11:1 on my 5.3's mainly cause I see plenty people running that CR on 93. Besides I have edit so i can always bump the timing back a degree or so if there is any pinging

have you looked into TEA or AS heads?? you can get stage 1.5 or 2's for 1300-1700bucks give or take on GP's

those heads might dyno 10-15less than the 2400-2800 bucks heads, but oh well Ill just drop 15pounds off the car to make up for it LMAO