I'm thinking I put too small a cam in my 360 Magnum...

I wish you luck my friend. I can't say I would purposefully build a nitrous combo with stock cast pistons. And if they weren't specifically gapped for nitrous, you could easily butt the rings and pop the top right off of them with 200. Be really careful with your timing, and read plugs every hit
Magnum hypereutectic pistons
Thanks