have the following figures stamped onto the crown of the pinto piston..therefore are these standard or has the block already been bored?

91.295c SP0.025 LYP

AE21426vi +0.50.

can we say what make they are from this?

At a guess, I'd say they were +0.50 oversize.

[Edited on 16/5/06 by owelly]

Yep AE make replacement/rebuild bearings, pistons, etc.

If you search for 21426 on Burton power you can see the +.5 piston in the results list.

Gary

thanks for that , it gives me a starting point, for the next step..