904 kickdown linkage question (swapping early (65) to later 904

you can upgrade to a 66-67 904 and it'll fit. It wasn't until 68 when the crank register and spline count changed. I'm not familiar with the early kickdown linkage but it sounds like Redfish is and he says it's different. That's easy to overcome though with either a Lokar or Bouchillion cable setup.