wow, there's not a lot of guys trying to hot rod 225 v6's.
you've probably noticed that....
this is primarily a v8 board so i don't know how much expertise we're going too be able to bring to bear on this.
i can tell you that all of the Buick v6's were derived from the Buick small block v8 family and that you can usually interchange parts directly between them. for instance, your pistons and rods would be a direct swap into a 300 and your timing cover would work with any Buick v8 from 215 ci (yes, smaller than your v6 ... it was an aluminum motor) to 350 ci.
as to interchange info between 225, odd and even 231, 3800s and 4100s you'd probably be better served on a turbo buick board.