if you have a L52 which you should (83 had a L52) then a L52HD from Marlin is what you need, NO a G52 or G54 or w56 will "bolt right up"
only the L will bolt up without cutting your driveshafts UNLESS you had the driveshafts from the same type truck,
the G and W trannies are about 6 inches longer than the L trannies, HOWEVER the L52HD that Marlin makes has the gear set from a G54 in the L52 short case, so you get the stronger G54 in a short case that bolts right up
