well in the real world cost vs. performance has to be considered. Thats why its funny in this argument people want to bring up engine masters where money is no object.
Why build a hemi if an LS can do it for a lot less?
more absurd lines of thinking. so if we stick with "this argument" no engine masters allowed, a stock rebuilt 360 with a cost of $800 and no special installation parts makes that the winner hands down. cost vs performance.
but that's not the real world, people want lots of performance. also in the real world if someone owns a mustang they will want to keep it ford. if they own a nova they would want to keep it chevy. if they own a duster they would want to keep it plymouth. ;)
so real world people want as much performance as possible and like to keep it in the family. that's why most don't spend extra $$$ to swap to a different brand engine.
most stick with an engine that fits right in, or if they do a swap they go for a swap that doesn't cost thousands. (Schumacher mods). Some will go for the thousands if they want big block / gen2 / newgen / lsx or whatever. but 99% don't want to spend thousands to swap brands of engines.