MawneeC5

iTrader: (12)

Ok, You guys Gave me great info on the 6.0 heads. Now for the other end of the spectrum. What about 5.3 heads?

Are there any adverse effects from the higher compression ?

How dangerous would the P/V clearance be with my cam(221/221 575/575 112)

Anyone here running them with any comments ?

Thansk in advance for any advice

My car is:
98 C5 6spd silver (faster! )
MTI 221/221 .575/.575 112 (Still stock tune,for now)
Comp 918s w/ Ti retainters
Fidanza Aluminum Flywheel and ZO6 clutch
High flow cats, Borla Stingers
Dual cone filter

orangeapeel

iTrader: (18)

You would be ok as far as PTVC with those heads. Higher CR would just give you more hp.

99blancoSS

iTrader: (115)

I'm running p+p'ed 5.3 heads. No ptv issues, numbers are in sig. Tuning is the only issue with the increased compression. As far as performance, my car gets out of its own way pretty good.

strokedls1

iTrader: (1)

All the stock heads will give you the same p to v clearance in an unmilled form. The difference is in the cc of the chamber. The cast design is a little different between the 6.0 and 5.3. The 01+ 6.0 heads used a ls6 style design while the 5.3's are more similar to a 5.7 head. I run 5.3L heads to get a smaller chamber to bump up compression. Mine are at 56cc chamber and work great. I would personally look into an aftermarket casting with all the new offerings out like the dart heads. I believe price on those is 1300 from summit.

AKRA

5.3 heads will work fine as long as you have milled off more than 0.010 to 0.015.

My 5.3 heads have been milled 0.010 and I have a 0.004 thinner gasket. My cam is a Lanati 224/560 112LSA with 1.75 rockers raises my lift to 576. My P/V clearance was 0.078 and the say you should go below 0.080.

You should be fine but if you ever plan on going larger later with the cam, you might think of LS1 or LS6 heads.

Good luck,

Al