Funny, I owned an 85 Fleetwood with a 4.1 and sold it with 200,000 miles on it, still running like new.
I knew someone who had an El Dorado with 280,000 miles on it. The body rusted off the car from NY winters, but the engine would not die.
My parents had a Northstar that self destructed at 100,000 miles (as expected with these engines) that was maintained perfectly. The 4.1 was fine if you maintained it and didn't overheat the engine. Northstars were the ones that are notorious for blowing head gaskets. I should know; I have owned Cadillacs for years, as well as having worked on many of them!
The HT 4100 from '82-'83 had multiple problems with head gaskets, worn cam lobes and leaking intakes, let alone being very underpowered. By 1984 they were improved, and in '85 the transverse mounted versions had adequate power.
The only good aluminum Cadillac engines were the 4.5 and 4.9 from the years 1988-1993.
Enjoy your 87 Caddy. I remember my high school English teacher would pick me up some mornings in her black 87 Sedan DeVille. What an absolute DREAM it was to ride in. I loved it more than the 1991 she got. The 87 seemed so small on the outside, and yet I marveled at how it drove like a much larger car (in the Cadillac tradition). Can't say much for the finish work on any GM products of that generation, but I still think the 87 Sedan DeVille was a pretty awesome little Caddy. Enjoy what you have!
I am third owner (my father being 2nd) of my cream yellow Caddie. It blew out a head, which leads to my question - is there any better FWD engine compatible?
Or must I purchase another Northstar?
I already have upgrades for the vehicle project, and I'm seeking a professional in the field here in Vegas.