what engine could I swap in?

This is posted in the Allante forum and it says you own a 79 coupe de ville?? If in fact, you have an Allante, what year??

It's a recent purchase.....1987 allante silver/red&burgandy.....seems I have a dead cylendar??{near firewall}...But last nite it shut down inflight..Error:Oil

Easiest thing to do is to install a 1989 through 1992 Allante' 4.5. You have to use all the original emissions equip and modules. Footprint is exactly the same. Exhaust manifolds, EGR valve, diverter valve, O2 sensors, and upper intake off old engine all need to be reused. I've never tried to put another non-Allante' Cadillac engine into an Allante'. I know the lower intake is different on Allante's that other Cad's and that is work to swap. Not sure about the heads.

Any body do a 350 chevy into allante???

Depends on how big the checkbook! 350's were never transverse engines, so you're in for alot of work when the 4100 might just be an injector that quit. And please add the Allante to your profile.

If you're looking for more power (maybe +45 hp), go with a 4.9L cadillac engine and swap over the Allante specific parts including heads and intake manifold. The extra power however might speed up the demise of the F7 tranny which was not known to be that strong to begin with.

If you can invest more money and want something with a lot of power and unique, install a transverse 5.3L chevy engine. It was used in the newer SS Impalas and some other models as well. With this engine, your car will be slightly faster than a 93 N* Allante.