[Mike C]

Stay under 220 degrees at .050 lift on the cam (Something like a Comp 268 or even 260 or Crane 272 or 266)

Heads are limiting factor with the early closed chambers, but they should work with cam that size. Make life easier if you don't go big on cam so heads don't have to come off to be machined for studs.

Intake mods (not sure that Offenhauser intake is exactly the best choice anymore. I'd look into an Edelbrock Performer for this application). The Q-jet is a good choice for a mild driver too IMO.

I'd skip the headers and run 2 1/2" exhaust with Dynomax Turbo mufflers (Hemi Turbos if it were mine.)