I have a 1968 18 spline, which I bought back in the mid-70's.
It is absolutely pristine, a few of the gears' dog teeth look brand new.
The question has to do with shifting.
In 1970 Chrysler redesigned the synchro rings going from the square notch style to the style with lugs and a rounded cutout.
The Mopar Chassis book says that the 71-72 synchronizer assembly is the best performing and that it "decreased the shifting effort on the 1968-1969 transmissions and also fixed any clashing problems that may have arisen in the older transmissions."
I am working on a 70 Challenger project, which will have a 512 RB with enough aluminum in the engine compartment to have a good weight distribution. The car will be a canyon carver.
Who has experience with both types of synchronizers?Are there reliability issues? (I remember cracking a synchro ring at the corner of a notch in a 68 383 Dart that I once owned.)
Are there issues with the old type that will make the car irritating to drive when doing a lot of enthusiastic shifting on twisty roads?
I have a set of NOS later synchros, but I would rather not use them to replace a pristine set of earlier synchros if I don't have to.
Robert