99 Grand Am Ram Air 3400 HO car.
 

Someone has offered me one of these cars for about $350. It supposedly needs an engine.

I'm thinking about buying it. Anyone had any success with these cars? And does the supercharged GP motor fit in them? It's an automatic car--black with tan interior.

Yes a 3800SC will fit. Since it is an auto, You will want to use the 4T65E transaxle that goes with the 3800SC. This will save you a lot of time in the electronics area since the PCM controls the engine and transaxle. Once you do the swap you may need to modify the PCM to turn off the Pass-Key feature or due some minor tuning. If this is the case there is a guy in Indiana who can assist you with it or if you have questions. His website is: http://www.gmtuners.com/

He does a lot of swaps. Mostly using Fiero's but he has done others as well. He is almost done swapping in a LS4 V-8 with the paddle-shift controlled transaxle into a Fiero.