Sounds like a nice set up you have planned, Jerry!
The 500 Caddy from an Eldo has the more desirable rear sump pick up
and rear sump oil pan that would clear the conventional front crossmember in your Burb.
If you use a rear drive Caddy 500 you may need to change the oil pan and pick up to one from an Eldo to make it fit. FYI, the dip sticks need to be bent differently (and carefully!) due to two different crankcase holes cast into the 472-500 blocks for Eldos vs. Rear drives.
The pans from the rear drive cars were kind of an odd shape with the sump skewed to the middle. I'm guessing you'll get the seat to fit; albeit tightly!
mike
