Speaking of the Vega, I recall seeing one many many years ago in Georgetown Colorado that someone had fitted with a V8. The engine was too tall for the engine compartment, so the owner had cut a large hole in the hood for the carburetor and air cleaner to stick out of. It didn't run well, it looked like hell, and the body was badly rusted out. But the owner seemed awful proud of it.
I had the opportunity to work on a few Vegas when I was an auto mechanic. One of the worst things that you could do is let that crappy little 4 cylinder overheat. If I recall correctly, the block had little/no webbing in the top -- the cylinders appeared to stand free in the water jacket. If you overheated the block even slightly, it would distort terribly to the point that the head gasket was essentially useless. Aftermarket replacement head gaskets for the Vega were incredibly thick...........