Hmmm... Today my poor brain was in overdrive.. I looked up the pilot bearing diameter for a 2.9. The OD is 0.8268 and the ID is 0.5906. A 460 of the same year (1992) has an OD of 1.8525 and an ID of 0.6733. So a bushing with an OD of 0.8268 and an ID of 0.6733 would allow the use of a ZF on a 2.9. Take the OD of the 2.9 and subtract the ID of the 460. It comes out to 0.07675. That would be the thickness of the bushing. I wonder is that enough for a pilot bushing? For 99% of people this is useless info, for anyone trying to swap a big block in stages... It's good to know for sure.