BillK the part number on the piston is H426P I hope this helps you some. If I go with flat tops will the drop to 9 to 1 compression hurt the effectiveness of the 292 cam?

I used a set of those in my last 454. With the stock 290 casting heads, I figured about 10.0 CR. Any lower than about 9.8 CR I would say less cam would make more power. I used a GM kit made by Crane...540 lift and 228 intake, 238 exhaust dur. at .050". Idled fairly good, and made more torque than the car could ever use.

Sammy,
That piston is a Sealed Power / Federal Mogul hyperutectic. I will look in the book when I am back at the shop, to see what compression they say it is and see if it will work with the closed chamber heads. It may not be till Monday.
Bill