The 46 I had in high school had a bad cluster and i had no luck in finding one (in my pricerange), in the junkyard I found a later trans partially apart, it looked the same inside except the bearings were loose needles instead of caged, and 1 less tooth ---it was all I could find, got a broken package of the needles to make up for the missing ones and put it together, turned smooth on the bench---put it in the car, ran quiet, survived many sidestep downshifts, and was still working when I sold the car ---I didn't know that it couldn't be done, don't know what the trans was from, it had no bellhousing, the job only cost me 2$ for the needles and the cluster was free because I had learned I got a much better price on any parts bought at that junkyard if I brought a small "bottle" that was full to match his many emptys every couple of visits
I don't know if your gear would turn out as good as it turned out for me (or if it would even work at all) but I was amazed how well it worked for me ---I just wanted first and reverse to work again