The original sun visors in my 74 2.0 are in near perfect condition except for the crunchy foam that I can deal with, but it appears the plastic framework has shrunk a tad.

They barely fit in the brackets and I have a feeling once it is back on the road in the Spring that they will unhook easily on rough roads.

Is there a trick in getting them to fit again? Some kind of extender maybe?

Based on what I think you're describing you should adjust the shafts and pull them out of the visor a bit more. If you loosen the screws you should be able to pull them out a little farther so they fit better in the holders. Those shafts are two different pieces and you can move them independently of each other.

Edit: should also probably point out that those screws can be used to adjust the amount of force required to move the visor, so don't crank them down too hard.

Sweet, I will try that. Thank you!

Loosen the screw on the visor. Use needle nose pliers to pull out the shaft to the correct length while it's hung on the plastic holders and tighten the screw on the visor just enough but not too much. Tighten the plastic holders to the car so they don't twist.