Anything will fit into anything if you've got enough gas in the torch, and a big enough hammer...
Just off the top of my head, there's no center sump oil pans available to clear the front suspension and steering, the turbo 350/400s won't fit the floorpan/tunnel, no exhaust manifold/header options that fit the early A, the mouse is a hair longer than an LA going into an already cramped engine compartment... It's been done, but it's far from easy.