40-year old car - EMP proof? Not unless you have acetylene lights and it's a (mechanical injection) diesel. Even then, if the EMP is bad enough you might have to crank- or bump-start it. I had a Rabbit Diesel (OK, about 30 years old it would be now) - it had electric lights, instrument panel, radio, fans (including engine cooling), starter, and glow plugs. All of which would be fried in a sufficiently large EMP. And under 55F ambient temp you could not start it without the glow plugs. No computers though.

Of course, unless it's a Mercedes (where the maintenance schedule seems to replace anything that could ever break every 30K miles), you do have to worry a bit in older vehicles about metal fatigue, rust, and other unseeable deterioration. Also: some of the safety stuff (air bags are rare in cars before the early 1990s; split braking systems weren't required before the late 1960s; crush zones, padding, and similar crash energy management items were primitive or missing in general practice before the late 1980s; no seat belts (unless added aftermarket) before the late 1960s); and general performance (even Ferraris before the late 1970s barely reach the acceleration potential of mid-line modern sedans; brakes were atrocious in most cars before the mid-1980s; anti-lock brakes were rare before the early 1990s).

IMO, the peak of car design was in the early 1990s, when they still had 5mph bumpers, other things including safety stuff were relatively modern, weight had not yet ballooned badly, and gas mileage and performance both were decent enough if the car was well-chosen. There were many good ones in the 1980s, but the safety stuff just wasn't there yet in most cars (though they did have 5mph bumpers and basics like collapsible steering columns and dash pads and, at least in the front seats, decent belts). Avoid the 70s like a plague (too many problems dealing the the new emission control requirements), plus Road Hugging Weight even in relatively small cars). After about 2003-4, things just got too big/heavy, and demand for performance hit gas mileage because of the power needed to move that mass around. Plus more changes in electronics to where cars are now just self-powered, rolling (and not always reliable) computer networks.

Since this is a RR board ... these car concerns are present with locos too. Certain older ones (GP9s, for instance) seem to never go away; they just get rebuilt occasionally. Lots of newer ones DO go away - perhaps problems with new or overly stretched engine designs, conversion from older electrical and control systems to computers, and the like. And the REALLY old ones that are hard to upgrade in place get scrapped with maybe a few going to retirement in museums (hmmm...sounds like me...).

Cheers!