Well, I took a big step forward on my project and dropped the engine and tranny into my 510. But in the process I ran into an issue I wasn't expecting.
It has an L18 and came with a stock 4 speed. I got a good deal on a 5 speed out of a 1979 620 (or so I was told). The transmission mounted up fine to the engine, but the transmission and shifter are leaning toward the passenger side. Please ignore the hack-job the previous owner did for me on the trans tunnel - that is one of the reasons I put the engine and transmission in the car.
Do I have any options beyond getting another 5 speed? Could I use the bell housing from the 4 speed?