c4 trans - what to look for?

Any c4 from 67-ish to 80 or so should work. A v8 version would be best, since stock, they have 5 clutches in the forward clutch, vice 3 on some of the lesser ones. 300 in six units are ok too. Just get all the parts, block plate, flexplate, bellhousing, etc that match, either 157 or 164 tooth, etc, the kickdown rod, etc. Make sure you get a torque converter and flexplate with the same bolt pattern, as there are two of those also. Note that there are 2 shift levers, one for column shift cars, and one for floor shifts. One points up and one points down. With an aftermarket shifter, either is fine, with a Mustang floor shift you need the right one(that I cannot remember right now). Be careful in looking at the 80 and up units, as a C5 is somewhat different, with a different valvebody and converter. It could work but will take more adapting. There are some mid to late 60's versions from Falcons that have odd valvebody features also. Early 60's versions also have 24 spline input shafts vice 26, I think.

I have two 164 tooth, case fill versions, with floor shift levers, both oem in Capri's. Work great.