I would call one of the custom piston guys, Wesco, JE, Childs+Albert, Arias, CP, Ross, ect...
And buy a couple of forged blanks. Most places sell them and that way you would be getting a good alloy and the grain would be right.
Most pistons are a very high silica alloy , not what you would find normally in billet .
Also you would have the pin bosses pretty much in place. As it is somewhat hard to get to the under sides of those babies.
Bare in mind that lots of pistons are turned "barrel" shaped not cylindrical. Special turning centers are required to do this.
Also the finish on the wall is very controled... by that I mean not smooth but controlled to retain oil.
Then there are the ring grooves and oil ring holes and gas ports and pin clip grooves and.......
Good luck. If you choose to accept this mission.....
