Nuts holding rocker arms

[scotty]

I got a head with different rocker arm studs than the old one and was wondering what the size could be. I already torqued the head down, so I can't take it to the hard ware store. The rocker assembly came with the head, so the studs fit, I just don't have any nuts for them. They need to be slightly smaller than the ones I had. I don't know what was in there to begin with, any ideas? Thanks