awaiting Cool84's post on this...
I accomplished this on my '84 GN... The brake pedal is hard as a rock... but it stops the car.
T in the return lines from the master cylinder to the reservoir is what I did.
I understand Cool84's father had accomplished a better swap than mine with a baffled reservoir (that may be part of my rock hard brake problem). He mentioned he was going to look at his father's setup and get us the information. This information should be installed in the brake section of the GNTType.org Tech section so others can readily use it.
Hopefully one of you will point this request to Cool84 so he can answer it. Thanks.