Dave the best bet is epoxy primer.. People will debate till the end of time whether its best to use an acid etch, then epoxy , or epoxy only, or acid etch then 2k etc etc etc..
For top notch work, IMO, using epoxy, then your 2k build primer for blocking is the only way to go.. Acid etch is yester years technology and while it was all good back in the day.. back in the day is gone..
I would also recommend that you strip that paint job.. start off with epoxy and work your way up.. I was not alive in 67, but I would assume its lacquer..
When you read of someone working off of an existing paint job and being told its okay to do that , they are speaking of urethanes and you could do the same with acrylic enamel paints, that have one paint job on them, not multiples..
Lacquer is porous.. Its a sponge ( read acid etch.. is a lacquer primer with acid content is all.. read dont use!!)..
If your paint job is lacquer as i assume, then you dont want that sponge underneath a fresh job.. Plus you dont know whats underneath a paint job that old.. You would be surprised what you will find often..
You will hear everyone talking about 2k.. that is just a name we use for urethane primers.. epoxy is called epoxy and base coat and clear are called what they are..
i would strongly suggest you start fresh and do it right... By that I mean stripping it and starting with epoxy..
Epoxy is the same resins as Ecoat.. the stuff they dip the cars in at the factory.. Only difference is solvencys between the 2.. One is bake only, while the other can air dry (epoxy)..
A little reading infor for you as well
etch vs epoxy
epoxy on bare metal
Bare metal prep
tac rag info
This should get you going.. I am sure someone else will chime in when they read this on Wed..