You can build a pretty snotty 360 with flat tops and a SFT cam. The money you save can get you the clutch and differential you'll need.
T-142F LA Solid Lifter Camshaft@Schnidercams 242/242 .510
273 rocker arms and about ..470~480" lift at the valve.
(5800 shift point).
Or, Howards Cams Mechanical Flat Tappet Camshaft; 1964 - 2003 Chrysler 273, 340, 360 2400 to 6200 Howards Cams 710862-08 if you want to run less compression.
(5600 shift point).