Late in the summer of '67 Brother Lon and I put together a TP 427 to go into his '67 Mustang. The manifold and carbs we got didn't come with the linkage. I knew Bill Coon and called him to see what he might have on hand. He told me he had a 'display' Cammer that he was using for parts and was willing to sell the linkage for 10 bucks. We met him at Milan the next weekend and he traded a sack full of pieces (Chrome, yet) for the ten dollar bill. When we tried to put it together, one of the rods was missing. He was indifferent---that's the last time I ever tried to do business with him--- but everything he gave us fit the TP engine just fine.
It's my guess that there'll be very little difference between low and medium riser linkage.
KS