“Until you can’t gets parts for it.”
Are you kidding me? I can easily get parts for my classic cars.The only difficult one is my 49 Chevy 3/4 ton, and for that I just swap out for modern parts, like the rear axle.
There is a huge aftermarket for small block Chevys. And remember, these are simpler cars without any computer assisted ash trays.
Small parts aren’t the problem.
Transmissions and engines are. Small blocks are still semi easy to acquire, depending on where you are, but in another 10-20 years it won’t be.
I can do a small block carb swap into my fuel injected 4 banger jeep easily enough if I wanted. Hell I can swap a ford lima 4 banger into it easily enough, but try doing an amc swap that’s not a gm bolt pattern or a ford engine into your GMs. I have a vast range of engine options due to the jeep aftermarket and amc’s love of gm motors that GM doesn’t have.