[mudmizer]

My 68 has the same set up. 465 & t-221. I got a lot of good info on this set up from the guys on the site. I think the 205 is a stronger t-case and parts for the 221 ane hard to find. After talking to some of the guys on the site I set up a spare 205 with the right tranny adapter with new seals and coupler. I was going to do the swap but decited to wait till the 221 craps out, if it doe's. One good thing about the 221 is that the rear output is about 5" lower than the 205. That is a plus for a short wheel base. I'm also told that the 221 has poor lubrication on one of the large bearings, so watch the gear oil level and keep it full.
Border Parts in Spring Valley (San Diego area) california carries parts for the 221 if needed.