426 small block stroker

You would have to pay attention to the;
Crank (340 or 360) and the
big end rod journal sizes. (Chevy or MP)
Rod small end sizes. (Chevy or MP)
Also, length and width.

Then find pistons for the rod and stroke into what ever bore size you intend on. Which you would know before hand anyway.
You may need to order custom pistons. That could run $1,000. More or less.