Just took the head off a 2.0 pinto and im after some info on the marking stamped into the pistons so I know what rings to order
 
                                                                            RA2526X 1.00
                                                                              TOP 0.04 B1
 
They have flat tops but on the side facing the front of the engine there is a small V shape notched into each one, whats that for?
 
Thanks

Front marker, think of it as arrow facing front.

Cheers

what does 1mm over take the displacement out to? if 90.7mm is standard bore size, 91.7mm wouldn't quite get you to 2100cc would it?

Standard is 90.82mm as far as I recall making 1994cc.  +1mm takes the capacity to 2038cc but I am not sure if +1mm means exactly a 91.82mm piston

RSMan did you find out what ring to buy ? Im building a Pinto with the same piston ID. Where did you end up getting your rings from ?
Cheers
Fahley