I have ran those pistons in both of my 383's. One had the .557 MP cam and the other runs a .630 roller. Neither required fly cut but couldn't go any bigger.

I have found sets of them on ebay for $50. I'll probably use them again in my next 383 as well and spend that $800 on better heads.

I ran them on eagle rods and getting clips/locks for the pistons pins was the tricky part.