Is the 340 internally balanced? The 360 is probably externally balance. Is the flywheel the same or do you need a different one like the flexplates. I have no idea but you should make sure your 340 flywheel is compatible.
The 360 flywheel is balanced for 360s only.
68-71. 340 are internal balanced engines and the 72-73 are external balanced.
The 340 external balance flywheels are not balanced for a 360.
