For the benefit of the newbies, or a reminder to the "memory challenged", there are many basic safety issues that should always be observed, whether you build it from the ground up, or finish someone elses project. These are common things you'll see.
Cotter pins. Ball joints, tie rods, spindle nuts and other key components have drilled threads and castle nuts. ALWAYS use new pins. I've seen nails, tie wire?? proper pins cost 25 cents, splurge. [If you are buying an unfinished project, check every thing designed to control or stop the car.]
Flex fans. If you are going to use them, check them. When they start to crack, toss em. True for any fan actually, but the flex seem more prone.
Brake lines. Unless they are factory, or you did them yourself, check em. Aluminum lines need a Double Flare. Surprising how many people don't know that. If you don't know how to tell, get someone who does. Especially check any newly installed pieces, like around proportioning valves.
Seat belt anchors. Frame members are best, but if it only goes through sheet metal, use at least a 3 inch grade 8 washer. Use grade 8 bolts and nuts. Never use the seat anchors, and don't use them for comparison. You weight much more than the seat, so the belt anchors must be 4 or 5 times stronger than the seat anchors.
Torque specs. They exist for virtually every bolt. Use em. Too light and they may come loose. Too heavy and it may stretch the threads and break later. Very common on over torqued wheel studs.
Axels and wheel bearings. Jack the car up and check each wheel for looseness, clicking noises, binding and grinding. It's amazing what you can't hear with the engine running.