Amanda Gaines

Hello!! I’m hoping to retrofit a 1966 Mustang to a 1967 style 303 top loader three speed manual transmission. I already have the transmission. Can anybody tell me what other parts I need, and do you have any idea where I can find these parts? I appreciate any input you can offer!!

imp

Most significant change done to '66 design in '67 was the WIDENING of the entire structure done largely to accommodate the much wider big block engines, 390, 427, etc. The '67 might also have been lengthened some, which would have changed driveshaft length in all likelihood; this I am not sure of specifically, and it can be easily researched.

The 3.03 Three Speed transmission was a heavier-duty gearbox than the smaller units used with small engines, and could be found factory-installed behind nearly any engine except the 406 and 427. It's mounting dimensions are basically similar to the smaller transmissions, and I see no reason why it could not be used in a '66 which was factory-equipped with a smaller transmission. Finding such parts today as originally supplied in early Mustangs may be difficult, but they were used in the other car lines also.