piston to valve clearence

[BADGMC]

I don't see that cam being an issue with what you have. I run a comp 274 extreme solid which is actually a lot more aggressive than the 286H and there is plenty of room. I would do the clay check just for the sake of doing it though. There is no such thing as checking clearances too much. Also, if you don't mind could you share some info on your 383 you are building. It bothers me when someone spends lots of money on a "wicked" combination and then they are baffled by it when it only goes a couple of tenths quicker than their old stuff. Many people on here have a lot of real world tips which can help a lot.