There is no more or less reason for fear of driving a 40yr old car then there is of driving a brand new one. Since '90 I've been driving all manner of car/truck the only times I've ever been broken down was
1. (1997) 1966 Malibu 230 i6, the rebuilt motor had phenolic timing gears and the teeth 'fell off' while I was driving. Dad brought a trailer and towed me home 80 miles.
2. (1998) 1984 Dodge D50 4wd, 2.6L Mitsubish motor, wrapped the rod bearing around the rod end..I did get a good veiw of the Hale Bopp comet that evening. Dad brought a trailer and towed me home 70 miles.
3. (2008) 1994 GMC stalled, would not start. Let it cool down and it started without any issue, later determined it was fuel pump related. Wife drove over to give me a warm place to sit while I thought about it, then I drove it home 2 miles.
Personally I feel more comfortable with the mechanical aspects of my '68 Mustang then I do of our '94 GMC, or the '06 Equinox, at least if something goes wrong I'll be able to point at it and fix it.. with the other two I could be chasing wires/wiring diagrams for days..
I doubt your current spark plug wires will work, but I don't remember which distributor you have. If it is a points style (even if it was converted with a petronix) then definately not, the terminals are different. You don't have to buy plug wires from Mike, but if you want good ones, you will. To get things running you can buy a generic set for a mid '70s V8, you might have to pick the 'best fit' wires, and you will have the longest ones left over for spare. Or you could buy a generic cut to fit set and crimp your own.
-ron