​​​​​​I had built a LS6 road race motor for a local SCCA guy a while back. He brings me the motor and I rear it down and one of the pistons burned all the way through the ring lands. I called him and asked if he was spraying this thing, he said no, he had slapped a cam in it and the tuner set it on kill. The detonation torched all the way through a piston in one track session. Wild, but it happened. Yours is not as bad, but was on its way. I would smooth all the edges on the pistons and polish the chambers on the heads since you have it apart. Wouldn't hurt

 

I had to open the bore to 4.130 7 pistons bad. Also lucky this happened with my old heads and not the new one's. Lucky I pulled them off because it was driving fine.

 

On the new pistons, totally worth it for you to soften all the edges. If you have not bought pistons yet, pay attention to the valve relief design. The ones in your motor now are huge and probably way too deep, plus it has a thin sharp edge right at the outer circumference. The deep trough will cause detonation points too. I think there is power in the tune from getting the piston design right. Since you got the Maat heads, you basically need a LS7 style piston since that head has that architecture. Look at the Mahle Power Packs. They are very well designed and have a killer ring pack.

 

Diamond #11586r

 

Updates?

 

Pistons just arrived last week and balancing is done.