Could a 4.9L go in a 1985 Eldorado?

[My_favorite_Brougham]

I come from the sedan section, so I am not too familar with the Eldorado. However, I am considering buying an early 80's Eldorado (I like the body). However, I have heard poor things about the V864, and the HT4100. However, I have heard that the newer Cadillac engines are very powerful (4.9L, Northstar, etc.) So, could a more powerful engine be put in an earlier Eldorado, say a 4.9L? Is this possible, feasible?

Please tell me if this is a non-issue with these smaller cars, because from my experience, the small motors don't do so well with big body Broughams, but I don't know about the Eldorado. I have heard from others that the 91-92ish range of Eldorados were quite powerful, and I would like that power in an '85.