Broke 3spd saginaw in '69 camaro and am considering getting a muncie. Does anyone know if everything will bolt right up with the same crossmember, bellhousing, driveshaft???

All you will need is a new shifter and possibly a longer speedometer cable. If you use a 64-65 Muncie your old spedo cable will work. If you use a newer Muncie the spedo cable connects on the passenger side.