Sound Advice

Bill:
You have recieved a lot of sound advice here. Copy El Coke's reply and keep it with you especially.
I think you can be very confident of the positive results Linseed oil will provide, as it remoisturizes and revitalizes the wood, and not just on the surface. Many prime coats fail because the users fail to anticipate that wood will pull moisture out of the prime and finish coats, which results in flaking and peeling.
I also strongly recommend Kilz oil based primer as a base. Frad likes Bullseye, I'd be OK with that too, but I've actually used Kilz, but be sure it's for Exterior use. Better quality Latex paints will be fine as a top coat.
Remember to allow for which sides are most exposed to the sun, as they need the most preparation. Static, or displayed pieces require this kind of planning more than ones that move around. Also, don't forget the effects of Colorado's dry climate, that is both a good and a bad thing. The bad part is minimized if you properly prepare the wood before you primer it.
If you can, try to get tracings of original lettering to aid in relettering the car. Often you can get better results than you would imagine, and you might find some interesting things.
Crayuft's comments are right, too, catch all the little holes and cracks you can.
Have fun,
Mike (now in the Building Materials Biz) Trent