The 301 is a short deck Pontiac block, and they had oddball head, so no other Pontiac intake will match up. You'd be much better off finding even a 350 Pontiac. Heads, with the correct intakes, are interchangable on all pontiacs from 287 to 455, with the exception of the short decks and ram air V. Your best bet would be to find a Pontiac engine built between '67 through '74, and there's nothing wrong with a 350. The early blocks didn't have sll the motor mount bolt holes needed for Firebird, but several venders now supply adapter mounts. If you don't want to put a lot of money into your drivetrain, shy away from a 455. They make so much torque, you'd have to upgrade everything. For a light late model car, you can't go wrong with the 350. Almost as much torque as a 400, with better milage, and everything but pistons will interchange. If you wanted to build a torque monster, both Jim Butler Performance (in Tennessee) and Pacific Performance Racing (in California) sell stroker kits (4" stroke) to make a 383 out of the 350.
If you need anymore info, PM me or just post here.
Bill