260H or 268H (318)

Would either of these work with stock components?

Yes, though if your going to keep the exhaust manifolds (It seems thatway) I would look into the Comp cams line designed for exhaust manifolds. Ithas a good bit more duration on the exhaust to help the engine breath unlike all the cams listed here so far.

First example, a car with Hwy gears; http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=634&sb=2
or
http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=635&sb=2

And the more aggresive cam. This should be able to provide a real nice power increase. I'd use this with 3.21/3.23 MIN.! gear or higher.
http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=636&sb=2