Ok guys here it goes, I have a stock lq9 with 317s I recently got some ported 862 heads with PRC 660lift springs, ferrea 2.02 intake and 1.57 exh valves, titanium retainers, multi angle valve job.. milled .030 now have a 58cc combustion chamber. I've been talking to alot of ppl and havnt gotten a consistint answer, so my question is are these heads even worth having on? Should I put my stock 317s back on or are the 862s an upgrade? What is my compression going to be with stock head gaskets on the 862s ? I've heard it will be over 12:1 an thats not safe on a dd. So I've looked into some .065 gaskets to bring the compression to 11.5 :1, does this sound right? I'm really needing done help as this is my dd and need to get this sorted out. Thanks.

 

Dont have pics of the intake port but the size difference is about the same as the exhaust side.


PerformanceTrucks.net Forums - youngbuck's Album: Go fast parts.

 

The better flowing heads or going to help Alot.. It's just your CR is too high. I'm thinking e85 or 110 octane & it would be safe.

Compression Ratio Calculator - Wallace Racing

 

I think your quench is going to be screwed up and wont run like it should. I went with 243s with stock head gaskets on my lq9

 

Idk how to use the compression caculater. What is quench?

 

Would I be better off putting my 317s back on? Or can I run this compression with a good tune?

 

Re: What is "quench"? What is a "quench area" Why is it good? n/m

This does a good job of explaining quench. You don't want too much room between your heads and pistons because it won't do a good job of mixing the fuel and air.