Reply to "bore size Hypereutectic pistons"

Yikes. No. Those pistons are set for .0025" piston to bore clearance.

A forged piston like the old TRW's need MINIMUM .0055".

You want rounded edge skirts on these things to reduce the cold start up slapping. .0055" is a lot.

You had better talk to Keith Black tech about this. Don't go by what I say or anyone else tells you for that matter. Do what the piston manufacturer advises.

Before you do any boring though you need to test that block for existing wall thickness.

Just because the pistons are made in a +40 does not mean it is a good idea to go that big.


I believe it is Race Tech that will make a piston in absolutely any bore size including the rings. So theoretically you could go to something like .031" presuming you can clean up the bores at that size. Good luck to that though. You might all clean up at .035 BUT you can actually use all different size pistons matched to each bore. They will make them that way for you.

The 427 Ford blocks are so scarce, that's really what is getting used for pistons in many of them.