We did one on an 88 earlier this year. We just replaced the cross and caps. You can take the old joint to a NAPA or a CarQuest, or similar auto parts store, and they should be able to match it up to a replacement cross kit. This will be cheaper that a whole new joint, but you will have to drive the old caps out of the joint, and carefully drive the new ones in. You have to be careful so as not to have the needle bearings fall out of the caps while you are installing them.  The trick I use is to pack them full of grease, that keeps the needles in place.

If you do decide to go that route, let me know and I can walk you through the procedure. But it will probably be half the cost, and your joint will fit back on without modification.