I found some info on the web that indicates the Cadillac 307 for 1986 was a carbureted Olds motor. It also sounds pretty gutless....

"A carbureted, Oldsmobile-built 5.0-liter V8 was the standard engine from 1986 to 1990. For 1990, a fuel-injected 5.7 liter V8 became available, but only with a Coachbuilder or Trailer Towing package. A year later, that engine jumped from 175 to 185 horsepower, and could be ordered for any Brougham. A Chevrolet-designed, fuel-injected 5.0-liter V8 became standard for '91, developing 30 more horsepower than the prior carbureted engine."

You can do as you wish, but I think I'd be lookin' for a 350 Chevy.....