mid 70's 360 harmonic balancers

The 360 harmonic balancer is not specific to whether you have an auto or manual tranny. As long as it's for a 360 built prior to 93 you are good to go whether it came from an engine with an auto or manual tranny.

You can't use the balancer from an internal balance engine like a 318 or 340 unless you want to spend so serious bucks adding mallory metal to the crank to make it an internal balance engine.

The 360 flywheel is drilled on the back side for the proper balance. Again as long as it's one for a 360 prior to 93. You can't use a flywheel from a 318, 340 for the same reasons as you can't for the harmonic balancer. But if you get one of the mopar engine books they usually have a template that shows you where to drill the 318, 340 flywheel so you can make it usable on a 360 just like they will show you where to weld the weights on the torque converter.

The 93 and up magnum 5.9 (360) engines have a different balance than the LA 360 through 92.