When I took the stock head off my motor, to install a Pro Design cool head, the tops of my Pistons were black. Is this normal? There were no pits in the pistons at all. They just had this black coating on the top of them. Any info would be great, thanks.

 

It is oil residue from your fuel mixture. This is normal. Over time you may get carbon build up on the piston and your heads. You should not let this condition get to bad.

 

Thanks.