I will add my two cents here, being fresh off an engine swap. I decided to swap in a 347, as it would be plug and play with my old 302. But while I was doing it, I realized I need new engine mounts as the old stockers were torn. While Im doing the engine, I may as well match the trans mount with the engine mounts. And my stock headers would be very restrictive, so I needed new headers too. My fuel injectors and MAF needed upgraded to keep the stroker from going lean. My stock throttle body would restrict power as well, so I better upgrage that. Ah, stock radiator struggles to keep a hot combo cool, needs upgraded too. Crap my old water pump is junk and fused to the old block. New engine deserves a new clutch right? New clutch needs either a new or at least resurfaced flywheel. Crap, that added power requires more fuel. Need to drop in a bigger fuel pump. Wow this 27 year old tank is really rusty inside. Better get a new tank and fuel gauge sending unit, or I may end up running rust through my new injectors and engine. Well, now its time for a dyno tune, better install a wideband so they can tune it properly. Whats that, my 27 year old ignition is cutting out? New distributor, coil, plug wires it is. Hey, this power is nice, but I cant stop very well with these stock brakes! And my suspension has the car all over the road when I floor it now!
My point is that dropping in a fresh crate engine will be the snow flake that started the snowball the size of a house. Everything else is so old and worn out on the car, you will replace all the things you would while doing a coyote swap if you want the car to function safely and correctly. Fix what you have, or be prepared to spend $6k, then $8k, then $10k+ in a hurry whether its with a crate engine or coyote swap.