How much of a HP gain will the 370 give you over a 350 (bore only - NOT the 370 stroker!)

I have a buddy doing this to his Shee and want to know what to expect. I wouldn't think more than 2-3 HP??? Everything else remaining the same.

 

Bump.

 

I just bought a banshee not to long ago and blew it up I bought.100over piston and I don’t know if I need to get a cool head or stay stock and I don’t know what else I need help if any one can help thanks