This might help you, I don't know.
I am rebuilding a 383 right now. The pistons are some kind of forging, the only marking is an "80" on the underside of the crown.
Anyway, the compression height is pretty close to 1.781. Well guess what, if I use a 440 crank and the 383 rods, the pistons
will stick out of the deck about .034". With a composition gasket and 906 heads, I think I can bring it in around 9.5 ~~ 10.0 compression.
The pistons are a flattop with a small trough valve relief.
With the 3.38 crank the compression would be around 8.2.
Almost 440 inches in a low deck block.
The counter weights will need to be cut significantly to clear the pistons with 383 rods, and the piston pin bosses may need some trimming if you use 383 rods and 440 crank. Additionally, if the piston rises into the combustion chamber of a 906 you'll want clay for clearance around the edges of the chamber. I have a 383 that is .020 positive deck and a .021 gasket. I had a chamfer cut on the piston head for clearance on stock 906s. It was too close for a .06" over 383. Combustion chambers are not round, but oval. They hang over the cylinder front and rear.
The other option is to simply cut the tops of the pistons. Most forged 383 and 440 pistons have plenty of material. I've cut .170"+ off the top of TRWs and Speed Pros.
