Would a Shovelhead engine and matching trans as well as the other power train stuff, fit inside this frame...

 

Simple answer is No, but I suppose anything is possible with enough skill and money.

 

In addition the stroke of a shovel is much longer than a Sporty, so the engine will be taller, which is most important for the rear head, plus the overall length of the trans/engine assembly is several inches longer. The Sporty engine unit is still the only unit construction twin the MoCo has made, hence is much more compact than any of the big twins.