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 tried putting it into gear by moving the linkage directly on the trans, the car just rolls like its in neutral. I should note that the engine came from a junkyard, the torque converter, too. I pulled the engine and double checked the converter, it's fully seated. I double checked vacuum lines, they're good. I checked if it was pumping fluid to the radiator, it is, a lot. I replaced the brown trans fluid with type f. I pulled the trans pan to see if anything was obviously wrong, some small sparkles of metal in it, I didn't know what to make of it. I'm not sure where to go from here. I'm planning and pulling the trans and getting a new torque converter. Any other thoughts before I do?