I've only ordered one set of custom pistons and it was from JE back in 2000 so limited experience. That set was for a stroker inline (4.120 stroke, 6.0 rod, 250 block) with a small "D" dish like a stock 250. Price was $100 exactly per piston for piston, pin, pin fit, and locks. I have to confess though that the pistons are still sitting in the box.

Surely JE or another manufacturer has forging or casting dies to produce 283 v8 flat top forgings. Move the pin bore up and that's it.

I'm willing to contact JE and get a quote. I'll work up some specs and post here for comment first. Any interest? Or if someone has a direct contact with JE or experience with another manufacturer that might be an alternative.