The 4 transfer cases availalbe in Squarebodies from 73-91 were NP203, NP205, NP208 and NP241C. All are passenger side drops, and all are manufactured by New Process. Here is a little information on all of them. And we'll add more info as the thread grows. Soon, we'll have all the transfer case info all in one thread which comes in handy for doing conversions and modifications.