Big-block Ford or Chevy engines are nearly 3" longer than a 351C, yet they "fit". One can trim & space the firewall access cover further into the cabin or move the whole powertrain backwards with custom engine & trans mounts. As long as you don't exceed the working angle of the halfshaft u-joints, and keep VERY close watch on their health, things seem to work OK. Note: since more cubic inches means a lower rev-limit, the conversions are usually slower (top-end) than 351C powered cars (unless you regear your ZF for some $3000); one can get about 500 hp from a stock block, why bother? Panteras and Corvettes with their full-independent rear ends do not make good dragsters, either. About the only swap that makes sense (in the US) is from a 351C to a 351W IMHO unless you are into street rod car shows. Most engine- swap cars wind up being converted back after the thrill wears thin.
