I have a set of 799 heads that I'm going to be using on my lq4 in my '03 rclb HD. I'm getting then milled and was looking for some advice as far as how much to mill, not sure what a good cr is. It's a DD and I have no plans on boost in the future at all. The current cam it has is a 218/222 .544 113. Im also considering polishing the ports. Nothing too crazy, just to remove the casting finish and smooth them out. I'm not sure what a good intake/injector setup would be with heads like this, but I'm thinking stock truck intake with 42#? Am I heading in the right direction here?

 

Bumping this, could really use some advice on how much to mill. They're out being resurfaced now and if I can get some advice fast enough I can get them milled. I'm planning on running a .051" head gasket and looking to get a static cr of 10:1 to 10.5:1. I'm running a low temp t stat and run a consistent 175-180 degrees, so a higher compression won't cause super high temps.

 

Just bolting them on will get you about 9.8-1( this is just a ballpark). You could prob go .030 and be fine.. I would have a good valve job done while you have them off.. Should get you close to what your looking for

 

Ok I'll just have them clean them up then. Would running a .040" gasket be worth it to get a slightly higher cr?

 

IIRC, milling them about .045-.050 will drop the chambers down to 59cc and net you roughly 10.8:1.

.030 is a good amount...

 

I milled my 243s down to 60cc or .030 with a stock mls gasket .051 its right at 11.1 according to advanced induction who did my cylinder heads. If you don't mill them you'll get 10.26.1

 

I have to cc them and find out where they are. The last owner had a lot of work done on his gto and I'm not sure if he milled them. Just had them resurfaced. I'll polish them and install the valves then get an accurate measurement.