Engine swapping was a great passtime, but this was way before the EPA and DOT, and insurance companies didn't give a darn.
Key vehicles would be a 48 Ford, Chevy, or Plymouth coupe, could pick these up for around 50 or less bucks with a very clean body that needed an overhaul, could unbolt everything forward from the firewall forward to see the bare frame, don't try this with a unibody. Low mileage V-8's can be had for around 60 bucks, Warshawsky had adapter plates and bolt on motor mounts.
Actually preferred a hydramatic, were bullet proof, 4 speeds, and with a torque converter, an extra 3X gear down multiplication for more rapid start. Could get brakes and suspension from larger vehicles of the same make for a buck a bushel basket full.
Wiring? About a half a dozen or so, didn't have to be an electronic genius. For a couple hundred bucks could leave spoil brat rich kids far in your dust. Called these sleepers back then.
New stuff? Have to get the entire wire harness out of the donor vehicle, very first part installed, would have to remove just about anything in your vehicle to replace it, plus all the electronics, slightly more than a half a dozen wires. You won't find any adapter plates nor motor mount kits.
Could get a cam regrind with a fixed cam, to extend the intake valve cycle, would idle kind of rough, but this was cool, 3/4 was a enough. But all this new stuff has variable valve timing, grind these cams, will be going backwards and much slower, it it moves at all. For one thing, will screw up the EGR, if it does run, your engine will be toast.
And make darn sure if you go through all this work, notify both the EPA and your insurance company, or may be in really deep trouble. Function of congress is to make laws, not only in automotive, but just about in anything else, really got carried away in the last 50 or so years.
Ha, was with GEICO for years, when I told them I purchase a Supra Turbo, that was the end of it. Telling them, don't you know a turbo gives far superior fuel economy? That sure doesn't work, had to find a different insurance company. Let's not talk about insurance premiums.
Ha, they didn't care when I told them my 1.4L had a turbo.