I just swapped a 390 Fe engine into my 1974 torino that originally had a 302. I got a new bellhousing to attach it to the old cruise-o-matic, I think it may be a c4 transmission. Upon starting engine for the first time, there was a really loud whirring sound coming from the transmission that got louder with more rpm. At first I thought that the starter wasn't disengaging the gear, but that turned out not to be the problem. I checked the transmission fluid and it was extremely low, I added a quart and the noise got quieter, but was still there, I added another and there wasnt any change. then, while checking the timing at idle, the noise just stopped completely at once. Then I tried putting the car in gear and nothing happened, I checked the shift linkage and it wasnt engaging. I fixed that but it still wont go into gear, the car just rolls like its in neutral, even in park. I should note that the engine came from a junkyard, the torque converter, too. I filled the torque converter with fluid before installing it and made sure I slid it into the input shaft all the way, it slid in further in three increments as I put it on. The transmission worked fine before the swap. I have yet to move the car at all with the new engine.