I think mostly swaps are done because it makes sense either cost wise, dimensionally or power wise. The sbc, was and is plentiful, cheap, realitively rugged and reliable. The LS motors are the modern equivalents. So as a mostly GM guy, I look at non Chevy motors in Chevys as silly, or at times, reverse snobbery. To do it seems counter productive, unless your goal is to agitate purists. Hot Rod Drag week just finished and there were A LOT of LS swaps in all makes, and most of the top Mustangs had LS motors. There was a '55 Chevy gasser that had a big Ford motor that ran very well and Finnegan's Blasphemi which won the gasser class. So there are exceptions, but I'll bet those exceptions cost more to build.