1996 Cadillac Deville engine exchange

I don't believe so, and I am not sure of all the specific differences. You definately will have some differences in the cylinder heads with egr passages and possibly mounting bosses. You might encounter problems with the crank sensor ports as well, the sensors changed in approx 1998. And there are differences in the front of the block to accomodate the different mounting. I could not say with confidence that you could. I know that the heads would be entirely different, somewhere they also made a change affecting head bolt length, and use of the wrong bolts could crack the block in the valley area.