I ran JE SRPs in my 505 blown alky.
That motor made 1200 crank HP. The tune was always safe, but the pistons had a bit of skirt rash on them for unknown reasons.
For my current 568, I went with Diamond pistons, and couldn't be happier. After 6 runs at 1600+ crank HP, the bearings and pistons look absolutely perfect, like they've never been run.
When the pistons arrived, I was even hesitant to use them. They looked more like works of art rather than something that would be installed in an engine.
Price was about 1200.00 for a set of custom pistons with 1.094 pins, pin buttons, rings, and 12 gas ports, using a .043.-043-1/16 ring pack.