the problem is not the engine fit as all the stuff to make it run in the right tune. www.eldoradocountry.com has a detailed story of replaceing the 4.1 with a 350 olds and what it takes. In the process Cory tells all of most of the other engine swaps you can do(Olds 307, cady V8's from early eldos of same body style.) and what throttle levers, computer modules, etc. you need to make it work.