360 Zero Balance Torque Converter

So I have a 78 360. New cast crank, harmonic balancer, and aftermarket flex plate.
Crank was balanced at the machine shop with h/b, flexplate attached and the machinist told me that I would need a zero balance TQ converter vice the weighted due to the good balance of everything.
QUESTION? Where due I get a TQ conv without the weight welded to it, or due I have to grind it off? Trans is a 66 904 in 66 Barracuda.