For a head I would go with a late model 225 without the "drool tubes" around the spark plugs, a port job (most of the power loss is in the stock slant head). If you go with a mild cam and a header you would have no problem with a Holley 450 cfm or even an Eddy 500 cfm.
I was ganna pick up a slant cam from these guys just because they have one in stock (or they can make one up), their prices aren't that bad, I have gotten 3 cams from them in the past, and they are local to me.
http://www.deltacam.com/
