4.5 or 4.9 into 87 deville

[derricknotorious]

what do i have to do to install either one of these engines i need more power and i want something reliable i have 115,000 miles on it now it runs good but i can hear the main bearings it sounds like a growl i heard all 4100s do this

[ctesla]

derrick,
the 4.1s were notorious for spinning bearings shortly near 120K.
but that is good for a Cadillac. I'd look into finding another used 4.1 with less miles to use as a runner, while you have your original rebuilt.
this will be the least expensive route.
a 4.5 or 4.9 will produce more power, but will use more fuel.
the '87 body design has remained "timely" and is quite sharp, if it is still pretty new throughout with the exception of the engine, I'd try to keep her original. if not, an engine swap can be done, but I'd also look into a newer Cadillac at that crossroad then. might be able to find a '94STS with lower miles for the cost of engine purchase and swap.
here in Houston, I just saw a '97 Eldo with 76K on the clock for $4500.
in Colorado, my brother just picked up a '99 STS w/42K for for 5K.
might be time to step up, but if you are like me, and she's clean inside, look for a 4.1 before going bigger.

and if Chicago won't help in engines;

Arapahoe Auto
Englewood, CO
Donnie Hunter, owner/operator
800-229-0875
303-781-0875

will have ALL these engines we discussed, and probably can freight them to your address for under $200-300.
I'd still look locally, as you might find a 4.1L in a local salvage yard with 77K and a 90day warranty for $650 total! (if you don't give a core)
this means extra crank, pistons, etc from your old engine, but even if you trade-in your old one, you'll still have: extra water pump, injectors w/ rail, brackets, mounts, TBI unit, manifolds, ALL the sensors, etc. that you can strip off and have as spares; this ALONE is a cost savings of hundreds of dollars (yes you might not use anything, but a couple of sensors or an ignition module, and your $100+ ahead of the game).

hope this helps,
chris
nrt racing