Overdrive Transmission Question

I thought it was the 518 that was the real pita and that the a500 was more of a reasonable swap?

Also, i've seen some threads on here where people used an adapter plate to do a 700r4 or even a 200r4 swap. I guess these trannies are smaller a fit in the tunnel a little bit better.

Their both a PITA because the OD unit is the same on both. The A500 is slightly shorter but not enough to make much difference. The 200R4 is the only one that doesn't require a lot of surgery to get it to fit.