If I am not mistaken the tranny to bell housing bolt pattern is different from the old standard GM HD 4-speed.I think the only factory bell housing you will find will have a provision for a hydraulic clutch slave cyl.
If you do use the aftermarket; the stuff from Advanced Adapters is real good quality like FJ-40 said. But becareful , I think that the bell housing they offer for the 4500 to a Chevy motor is the Factory piece - so a bone yard may be cheaper.
You should be able to find one out of a 1992 and up 3/4 or 1 Ton GM truck.
Good Luck , Thomas
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1984 K-30 w/ 292 / CH465-NP205 ( 32 spline )Dana 60 / GM 14 bolt - 1410 series u-joints / TBI
