i have done several of these old diesel blowers, any 71-series blower (regardless of manufacturer) are the same, except the detroit blowers often have 2 little "lips" on one side that they hung on (as they were mounted sideways) but they are no problem.
the cases for 4-71, 6-71, 12-71, 14-71 etc are all identical except the 4-71 has three mounting holes, and the lengths are what differ, so all case covers are interchangeable and the top plate and bottom mounting surface (except 4-71) are all the same until you get to 12-71 which has a 1" longer opening in the rear but the same bolt-pattern, the top plate stays the same all the way to the biggest one which is 16-71
the rear plates are almost always a wet bearing setup that ran a fuel pump off of the rear of one of the rotors, it also has an oil slinger that bolts to the back of one (or both) of the rotors so you need to call bds to get a rear plate that accepts sealed bearings (i have a mooneyham one i can sell you too)
the opening on for the drive on the front plate is the same as any aftermarket 71 series
as are the holes in the drive gear that bolt the drive to it.
so what you need is a 390 manifold (the 390 is absolute most expensive one offered)
a rear plate, and then a drive kit, which are available in different lengths to clear different accessory setups. and in v-belt, serp belt, and varyng widths of toothed kevlar belts, with varying pitches on the teeth as well
now some of the detroit diesel blowers have a 3-bolt triangular opening mooneyham makes a cool little cover for that with their logo or you can make your own, or you can get a new front plate from bds that doesn't have that, but it does have the little release valve that you can push to vent excess pressure in the case that builds up so that oil doesn't force past the seals and into the crankcase, because the front does have gear oil in it to lubricate the 2 gears
see in this pic
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, now im starting my research on how to make it work on a 390
, fabbing an adapter plate to bolt the blower on will be easy enough, its converting it over to belt drive that will be interesting..does anyone know of any companies out there that will put a belt drive on a gmc blower?? any help would be greatly appreciated!!
