Seems like a lot of cam for a 273 and only 2300 stall. Ill bet real compression is closer to 8.5 to 1 if that. I would go two steps down from that cam in the voodoo series. If the original heads are open chamber the 302s will give you a compression increase if not it a wash. Make sure you use Mr. gasket .028 thick gaskets from summit racing. Stock replacement felpros are around .050 . Just my opinion. There are a lot smarter people on here than me.