00 Z71 Sierra

ive got a lq4 long block to work off of...

im thinking....

p&p/milled ~.020 ls6 heads
~.040 head gasket

will i have any ptv issues?

undecided on a cam.....recommendations?

tdrumm

iTrader: (18)

Where did you decide the amount to mill the heads and gasket thickness? Is there a specific compression ratio or chamber volume that you are aiming for? Or is it to get back lost compression due to the porting process?

Piston to Valve clearance has many factors: Piston dish or reliefs, milled heads, and thinner gaskets all play a role in determining p to v, but you also must have a cam in mind. Cam duration and lift play the most important roles in determining piston to valve clearance. I've read that .080 intake and .100 are safe minimum p to v clearances. The only way to be 100% sure is to clay the engine when you are doing the heads.

As for a cam recommendation, I would call a cam grinder and speak to them. Tell them as much about your truck, driving style, and engine combo and see what they say.

00 Z71 Sierra

reason i wanted to mill the heads was i was hoping for around a 10.5-11:1 CR

im trying to make about 450hp at the flywheel while staying N/A

can this be done with the stock lq4 bottom end?

white1

iTrader: (5)

Not to thread hijack, but Ive been tossing around the idea of swapping my 317's for a set of hand P&P LS1 heads. Would the increased compression make up for the lost flow? I know the 5.3 heads boost the compression way up, but the heads dont flow too good at higher RPMs due to the small valves. Just wondering how much flow I would loose with the LS1 heads, I plan to P&P and mill .020, or .030. I have a LQ4, so I have some room to go with the compression. Id like to be around 10.5-10.75 or so.

02sierraz71_5.3

iTrader: (2)

its all about the dynamic compression, you should be paying more attention to that than static compression. I wouldnt worry to much about p/v if you go with a cam in the .56x lift range and under 230 duration. you can always clay the heads