not sure if older trucks but for my 97 ive been told to make sure and use the push rod from the hydroboost onto a hydroboost master cylinder. not sure if older ones where the same or not.
the swap looks pretty easy. but then again i have one for my 97 already and im just to lazy to instal it in my truck! only thing i need is some new lines for it since i got mine from 2 different trucks. i got all the main firewall parts from a HD truck 454. and later i found a 350vortec with the hydroboost on it so i bought the front ac/powersteering bracket and PS pump on it. i also bought a decent looking cooler but the lines where already cut, i think i just need some barb fittings and clamps so i can still use the cooler.
and from what ive heard you can use your stock PS pump you just have to T into the return line and it should work fine. but then again its probably better to run the real hydroboost pump since it has 2 return lines into the pump so it should flow alittle better.