1985 Aero NB50M /NQ50 PISTON SIZE?

[shotcaller]

..take a look at the spec list for piston of the same year here only difference is jug shape. Says bore specs match.

Be careful about assumptions regarding bore/stroke specs. 1984-85 pistons have a dished (low compression) top. 1986-87 are domed. Thus skip the early Spree piston. There are ring physical differences too, be sure to get a set that matches your piston.

[MrJumps]

Look for a super cheap replacement bore on ebay and see if it will turn freely with it, then buy the better bore.

[Wheelman-111]

Greetings:

The fact that the bore diameter is identical doesn't guarantee that the location of the wrist pin and the piston top will sit on the same plane. The effect of a big variation on these critical dimensions will be a change in port timing, which will make a substantial performance change - for better or worse. Get the piston that was specifically designed for the bore.