Headders, better cam and better carb. And if the engine is in good shape, increase compression a little. Mill the head .040".
What carb is something complicated, because here You have two troubles: cost and smog. Smog is no problem, I'd use a Holley 450cfm, mec. secondaries. And a Clifford manifold. As for the cam, I'd use either a Clifford or a Isky supercam 266. You'll have to call them to grind this one for You, because I think they will not have one waiting for You.
This is what I'd done to a 292 if it were mine.
