What Tommy is saying is that since you have a trans from one era of truck and a column/truck from another, no linkage fit's outright. This is probably a simple modification. In these situations it would be nice to have both linkage sets. You would see what each "end" looks like and the installed tranny and column right there for the lengths. You could even weld the "ends" together and make the modified linkage or use the two sets as templates for new rod stock. Bend, thread and drill the rod stock to fit.
TomTom's idea would be easier.
The real solution is to buy and install a SM420 or SM435 4 speed truck trans. No linkage at all.
Column shifts, that need modified for a different trans, can be difficult if you are not a experienced fabricator. Maybe yours is not a difficult fabrication. Don't know. The throws, direction of lever rotation and clocking can be very different. There are limits of movement on the column side. I'm sure someone here has done it.
