The offy had to be converted to be able to have a Ford flywheel, clutch and bell housing mounts.
...and a starter.
Instead of converting the hilborn mechanical fuel injection they built an intake manifold for huge stromberg carburetors.
They fought vibration so they mounted the carbs solid under the left fender (right next to the butane powered air horn) with rubber radiator hose going to the manifold. The distributor drive was also shaking so bad that they eventually used a torsion spring to drive it. If you don't have a dyno you don't know anything.