Converting a 3 speed manual to 4

Pretty straight forward. Change transmission with one from another 65 and earlier with the flange on the output. Use 4 speed shifter and linkage and install a floor hump. The clutch and linkage is the same on both. The way the trans bolts to the bell is different between them so you will need to be sure the bellhousing is drilled with both patterns or get a different bell.