I just transitioned my 1970 914 from tail shift to side shift. The dilemma was what to do for the firewall bushing since no one makes the firewall transition bushing anymore.
Bruce stone sold me the set of side shift linkages. With it, I asked him to cut off a 6 inch length of the tail shift linkage that goes in the tunnel. It just happens to slip right over the side shift tunnel link. There is some slippage, but it is tolerable. This six inch sleeve is the rusty tube in the photos.
This allows me to use the same tail shift firewall bushing I already had in place. When I put the side shift linkage in place, all I did was push the sleeve as far back as I could against the knuckle joint and used a sheet metal screw to hold it in place. see photos.
So that all the tail shift tunnel linkages don't start disappearing from people cutting them up, I am certain an equivalent stock tube size is available that will work.
Works like a champ.Click to view attachment Click to view attachment