Edelbrock Performer 5.0 (6037) Heads Pitting Damage
** UPDATE - Edelbrock replaced the heads free under warranty **
** Big thanks to them **

Click HERE to see the new style (60379)heads they replaced them with.

Notice the pits in the quench area of the head. They are fairly deep. I estimate at least 0.010 inch or deeper. The engine did detonate briefly, but no other damage is visible to the valves, pistons, plugs, combustion chamber, piston tops, etc. like you would expect from detonation or pinging. All cylinders have this same pitting. Some are slightly better than this cylinder, but others are worse.

Most believe the damage below was caused by a poor casting.  It may have been due to old molds that Edelbrock has been using since these heads have been around for quite some time.

close up of quench damage
Combustion Area:
quench damage
Whole Cylinder:
whole cylinder

Notice the aluminum has eroded away near the water jackets. The reddish color was silicone RTV used to "fill in" the metal for the gaskets to seal properly. This occurred prior to the quench area damage. Due to aluminum erosion from this and the pitting, is it possible the heads have casting flaws or perhaps poorer quality than standard aluminum?

Picture 1:
water jacket erosion
Picture 2:
water jacket erosion