I'm at the point of my restoration where I need to send the tranny out to have it rebuilt. Just had the motor redone and the transmission is next. It has the non synchro 3 speed which I believe is referred to in the shop manual as the 2.77. It was rebuilt 37 years ago when I purchased the car and then 7 years later after 60-70k more miles. It's not seen any miles in the last 20+ years but just before I parked it I knew it needed attention again. When asking around for a reputable mechanic, a distance acquaintance suggested I might want to upgrade to the synchronized version. He had done something similar on his 66 and it required changing a few parts so it would bolt up correctly but he said the big advantage was it would last much longer than the 2.77. A 200k transmission versus a 60k mile if you will. I don't mind the non syncro because that's all I've ever known with it and want to keep it as stock as possible but the durabilty has me questioning how to go about upgrading to the 3.03 synchronized. Seems like when I bought the car my dad and I looked high and low for transmissions to replace the bad one that was in it. They were plentiful except none of them would bolt up correctly. Obviously we were not comparing apples to apples and being more familiar with mustangs now I realize we did not have a grasp on what we were looking for but at the same time I realize there is more to it than meets the eye. Can you guys shed some like on my predicament and suggest a path forward?