Anyone have any numbers with a 6.0 with milled 5.3 heads??? Just wanting a little more and have been thinking of this. Wanting to mill a set and stick on there. Let me know if anyone has anything...

 

Milling to achieve what CR? I'd think that going to the 5.3 head would be a downgrade (unless ported too?)

 

Also you will have to get bigger valve's to make it work.

 

x3

If you are going to go with 5.3 heads you need to get 2.0 intake valves istalled and have them ported and polished to get them up to par with 243's and 317's flow numbers. If you dont do this the bump in compression will be canceled out with the poor flow numbers for that many cubes. Just my 2 cents.

 

You would need valve work, valves to be a decent upgrade on the 5.3's If you want comp slap a set of ls-6 heads on there. They flow just as well as the 317 heads..

 

They would definately have bigger valves, be ported, and I'm wanting to have about 11.0-11.5 CR. Valves would be about the same size as on my 6.0. 2.02" intake and 1.55" exhaust.

 

Sorry. I should have been more specific.

 

just my opinion here, I would never go over 11:1 on a street truck. It's really not worth the minimal gains to always have to be worrying about getting good gas.

 

Go with LS6 heads 243, 799 IMO.

 

if youre running a lq9 motor do NOT mill the heads, it will bump your cr way to high just go with a stock gasket, i ran a set of patriot 2.5 heads with 2.02 valves and put down 400+ hp. the cr was close to 12. somewhere around 11.5:1 if youre using a lq4 i would think the cr would be less but wouldnt mill them neither just use a thinner gasket to achieve the cr.