70 challenger.

New here from the 4abody’s only but I’m going to buy a 70 challenger and it needs a motor I have a 68 440 that I’m building and a 340 that has a 508 cam m1 intake 750 carb forged pistons ran 12.7 with 355 gears and street tires. My question is which is the better choice for the combo and weight.
Author: Moparhead