Swapping out a 472 7.7L for a 500 8.2L in 68 DeVille?

Hi All,
 
Just starting to learn about rebuilding/restoring. I want to know if I can replace the engine of a 68 DeVille with the engine of a 70 El Dorado. What issues would there be with doing this (size, compatibility, etc...)?
 
Thanks

Eldorado is front wheel drive and Deville is rear wheel drive, that is the first thing that comes to my mind. probably not an issue however.  For 1970 Cadillac stroked the 472 V8 to 4.304 in increasing total displacement on the engine up to a full 500 CID. At introduction it was rated at 400 horsepower SAE gross, and 550 ft·lbf of torque . That makes the 1970 Eldorado 500 one beast and one of the all time torque masters!

It should be a straight bolt in.you will need to used old exhaust manifolds.Area of concern is with starter and flywheel. Eldo starter mounted on transmission. I would make sure block is drilled for starter to mount to it.