All of this has made me curious, so I did some research. The A and B bodies take the same number rear shock. The Imperial does take a different number, but is nowhere near as long as we've thought. Here are the specs:
The Imperial shocks are not much longer at all.
A&B body:
http://gabriel.com/our-products/car-...?partnum=82131
Imperial:
[URL]http://gabriel.com/our-products/car-...?partnum=81469[/URL]