383 build help one piece at a time

That's the thing ...my machinist wants the pistons before he starts boring.... So I'm starting from the bottom up and will match the cam....I was going to use the 516's with a light port stock but I'll do the bigger exhaust valve if you guys think it make a diff. .....so would this piston be what I'm looking for? I think it is as the 516 is like 78cc so i should be over 9.1 or better on compression ....

Do I just do the hardened seat on the exhaust valve or do you always do both? Thanks

http://www.jegs.com/i/KB-Performance-Pistons/648/KB162.030/10002/-1?parentProductId=755794