Having just read "MURRSUE's" request for help on a Ford based E-Brake, I thought my "find" might help someone looking for a unit to install into a GM 10 bolt/bucket seat floor mount.
While "harvesting" parts at the AutoWrecker for my '39 Chevy project, I looked at a floor mount system in a 2000 Honda Civic. To my surprise the entire arrangement, from floor mount lever > brake drum cable, was a bolt-in to my GM 10 bolt rear end. That is, cables from a Civic drum work in GM drum, and cables leading to the Civic floor mount lever installed my (Mazda 929) bucket seats are of suitable length, when installed to a '39 Chevy.
I know! I know! Mixing US and Off Shore parts -------- but, it works. And, for what it's worth, the e-cables/sheaths are, in my opinion, better designed. GM's are spiral wound, metal sheaths which, over time, would rust and seize up, while the ones I found are "neoprene/watertight" units.