Swap 904 to 727?

Been awhile since I was on here. How are you all doing. I appreciated all of your advice last month and I am back with another question. First let me fill you in on where I am at with the 66. Still waiting on my mechanic friend to get here to see if we can start this 318 on its cradle. He has the Edelbrock 4 barrel doing rebuild on it. Found that man in Oklahoma who has an 8 1/4 rear end and he wants this 69 340 front end I have. Hopefully going this week to make the even trade with him. I may not install it for a while though. Got a lot of irons in the fire.
The question I have came about when I told my mechanic friend that I had already put the 727 on the back of the 318 and I was telling him how I had install the flex plate and attached it to the torque converter. I mention that the fly wheel had balance weights on it. He said the 318 was internal balanced and the balance weights would have to be knocked off of fly wheel. Does this sound correct to any of y'all? He did ask about the harmonic balance. Something about its shape. Don't remember exactly. The 727 is a 72 and I think it came off a small block.