Pretty much ever since I installed my heads, my car has been pinging under heavy load. For example, if in 6th gear going up a hill, and you maintain speed with the throttle, it will sit there and ping the whole way up the hill. If i shift to 5th and bring the RPM's up, it wont do it. It will also do it under high RPM heavy load as well, but it doesnt do it nearly as much.

Mods are as follows:

AFR's milled to 62cc
.040 Cometic head gaskets
Stock shortblock
FM13 Cam (112+4)

It was pinging at 28 degrees of timing, so I reduced all the timing tables by 2 degrees and it still does it. I calculated a SCR of 11.37 and I run on 92 gas.

Do I need to try a thicker head gasket? Higher octane fuel? 92 is the highest I can get around here except cam 2 for $5.50/gal. Anything I can do on EFILive to fix this?

Thanks!
Josh