2018 was my 10th Drag Week, so I have had a lot of opportunity to analyze failures. I built my car largely based upon what I have learned.
Valvetrains with stiff racing springs are a major point of failure.
In my 392 Hemi, I used bushed Isky lifters with full time pressure oiling to the bushing. I tapped into the main oil gallery and ran an oil line to each head to provide full time oil, unrestricted. I have 2 -8 AN drain back lines added to each head, dumping oil into the pan. I use Missle aluminum rockers that are drilled to oil the rollers, the pushrod tips, and the springs. The Missle rockers use bushings on the shafts. Some one in previous years turned a bushing, it blocked the oil hole, and burned up a rocker. So I pinned each bushing with a pair of 4-40 set screws, red locktighted in so the bushings cant turn if they get hot.

I drilled an .020 hole in the rear internal oil gallery plug that sprays a stream of oil on the distributor gear.

Every important fastener on the whole car, except for a few like lug nuts and stuff we take off like exhaust bolts and valve cover bolts is either ny-locked, safety wired, double nutted, or lock tighted.

Electrical gremlins are a big thing. Every connection on my whole car is soldered so nothing can rattle loose. I have extra relays and fuses in the tool box. All wires and lines need to be shielded from exhaust heat.

Make it simple to work on. Nothing should be in the way of your routine tasks. There was a car where they had to take the line lock off the fenderwell to get the valve cover off. That kind of stuff is a no-no.

I use a gm alternator from a late 90's pick up, and a chevy HHR radiator fan. They are in stock at any parts store.

I use an MSD ready to run distributor, wired thru an MSD 6 digital box. If the MSD 6 fails, I have a pigtail in the tool box, that with plugging it in, the car will run off the distributor only, no box. I carry extra cap and rotor.

I have some scary stuff that I took risks on, but am looking at back up plans for next year. Like a Mezziere water pump. If it broke, what would I do? I should probably get a spare. And no spare tire. But I did bring a tube, a patch kit and a compressor.