The 340's, when new, were able to punch way above their weight class The perfect combination of bore/stroke, carburation and camshaft and in the perfect size chassis. Kind of like a 327 in a Chevy II.
I street raced a bundle of them with my '64 GTO, '70 Cyclone GT, '63 421 Gran Prix and others that went thru my hands. Tough to beat in any situation.
If I were to build a street friendly daily Mopar with a small block the 340 cam would be what I'd want. Just enough snot to make your opponent think twice especially if some $$$ is on the line.
I would call Howards, Lunati, maybe Comp, Bullet and see if they can grind you a custom copy of the 340 4-speed cam...maybe with a touch more lift and duration. Just a touch... not too much.
BUT... get it ground on a Mopar .904 lifter friendly core. It makes a difference. The factory thought so. The Brand X guys regularly use .904 lifters for a reason. Anything less is going backwards.
Sounds like a fun deal... burn some rubber for me when you are done.