Easy carb'ed 300 mods:

Offy/clifford "open plenum" intake, Motorcraft 2100 2bbl (1.08 venturi), and EFI exhaust manifolds or headers. That'll increase power everywhere on the carb'ed 300, and extend the "meat" of the power band another 1000RPM to 3500 (or so).

Next step is a mild dual-pattern cam (260-270 advertised duration), with no loss in low-end torque, and power out to 4500RPM.

300 has 7 main bearings, 4" stroke, and huge cooling capacity. 300 pickup owners often have to cover part of the radiator in the winter to keep the trucks/cab heat warm.

Good luck!