Usually, people install the V6 master cylinder with the V6 brake booster. The difference is that the V6 master cylinder has a larger bore, (Which is needed with larger calipers) which would normally increase the pedal effort, but the V6 dual diaphram brake booster reduces the pedal effort overall.

Converting over to V6 Montero calipers and rotors really increases the stopping power on the older models. On my buddy's '86 Montero, I used '95 SR Montero front brake parts (Two piston calipers/thickest large diameter rotors) with a junkyard '89 V6 booster and new '89 V6 master cylinder, with '88 Montero 4 cyl rear wheel cylinders (1/16" larger than the '86 ones). Really makes a difference, and the parts cost about the same as stock replacements <img src="/forums/images/graemlins/kewl.gif" alt="" />

You would have to ask the experts here or study the parts manuals to see if the '84 D50 (4x4) uses the same brake pars as the early Gen 1 Montero, if so, then the V6 Montero parts upgrade will work! Note: The Gen 1 V6 Montero brake booster may or may not bolt on to the firewall. I think there were some V6 D50's/Mighty Maxes which might fit better if the booster is differently mounted between the trucks and the Monteros.