Started the Heads/Cam install today.

[secondgearscratch]

with the stage 2.5's that I got 2.04 valves came with them. A valve upgrade is a must have with 5.3L heads. Personally if it were me and was going to home port my own heads I would keep my eyes out in the GTO crowd for someone dumping their stock 243's and port those. I wouldn't have the balls to try and port my own heads. I don't have the knowledge either. You can actually lose HP if they're not right.

i hear what your saying. its a fairly exact science but i have a friend who did his and to make a long story short, he runs upper tens with a maigc stick 4 and an expensive tune. im not completely sold on the idea of doing it myself, and the more i read the more i realize just whats at stake. having the port angle right to (i guess?) increase the velocity of incoming air, or like you said, it will cause you to lose hp. im pretty novice in this respect with all the internal trials and trappings but i figure the easiest way to learn is to just do it. if i screw it up, atleast it wont be brand new parts and i can take knowledge from it and do it right the next time. how big are the exhaust valves in the truck heads? and what springs and rockers are you using. i assume they are the same ratio to the ls1?

[0rion]

hey, I'm all for just diving in and learning as you go. The problem with heads is being able to check your work. I suppose if you know someone that can flow test them for you so you can see if they're better or worse would be nice to have. I would have to look up the valve sizes, I forget them off the top of my head. I'm using patriot gold dual springs with my stock rockers.

[secondgearscratch]

hey, I'm all for just diving in and learning as you go. The problem with heads is being able to check your work. I suppose if you know someone that can flow test them for you so you can see if they're better or worse would be nice to have. I would have to look up the valve sizes, I forget them off the top of my head. I'm using patriot gold dual springs with my stock rockers.

ok, i will see if i can persuade a few goat owners into selling their shit. again, thanks for all the info. im feeling alot more prepared for this now. plus it doesnt hurt to know this now, i think im going to wyotech next year.....

[juiced99ws6]

my roommate has an 05 gto with L92 heads waiting to be installed but as of right now his 243 heads are spoken for if anything falls through then ill post up on here, i know he is gunna want to sell them

Sorry I didnt realize that the 5.3s had smaller valves, I just know they are a good head to go with once they are worked over.

[mrr23]

but you could port the intake valves couldnt you??? i dont know what that would do for cfm but..... what would you do? port out the stock heads? i dont have the money for something like afr's or patriot's. i havent really looked at the z06 heads, but i cant imagine there is a huge difference.

yes, you can cut the seats to fit the 2.00 valve from the 1.88 it has now. problem is, the larger valve gets closer to the wall of the chamber, thus blocking airflow. when you hear about people having 5.3L heads on their car, it's because they bought them from places like patriot, thunder racing, etc, already ported to make more flow and unshroud the valve area in the chambers.

just putting a set of 5.3L stock heads on a 5.7L LS1 motor will not achieve the same results.

just save up the money for a good set of heads. or, maybe, find someone selling their ported heads.