[357ford]

I know a fella that has speed pro pistons with coated skirts, the paper says that the bores need to be overbored even further for these to fit. These are .060 pistons and the bores are .060 but the paper recommends the bores be taken out further to compensate for the coating.

He tried to drop them in a .060 over block, without rings just to see and sure enough they weren't gonna go in. As a matter of fact they recently came out of a .060 block.

He is wondering how much more should the bores be taken out on average to compensate for the coating, just in case the machinist doesn't seem to know, I'd like to give him some information to fall back on.

Thanks

[stepside454]

the paper work that is with them should say how much piston-wall clearance is required...so you measure the piston, & the cylinder should tell you what you need to know

[357ford]

I am gonna guess and say the paper didn't give any clearances, maybe that part is missing or it wasn't included. Suppose he needs to call a speed pro rep if not speed pro.


Thanks though