I bought a w114 250 sedan without an engine because someone put in some high power toyota inline 6. There are some small/narrow v8s. Maybe a buick 215. Ford 289 must be narrow because it fits in a Sunbeam Tiger.

As for my 250, I have a 280 carb engine with a manual. I will do what I can to improve intake and exhaust flow. Eventually get hotter cam for it.