This is a 383 I bought and the guy said it had never been run. It has been together for over 10 years just sitting in the guys garage. It is a nice old school build - 906’s, 509 cam, TM-6, Demon 850.

I have searched the internet and can’t seem to find any details on this piston. I saw one on Mancini’s site that seems to have the same shape of relief in the picture, but the description said it was a 5cc relief. I am just having a hard time believing that is 5cc relief. I am going to try to roll it on its side tomorrow to see if I can at least get close to measuring, but thought someone on here probably knows exactly what it is.

Thanks