There's a guy in Australia making reverse ring and pinions for the Subaru tranny's so you can use the Subaru setup rear engine.

On the 4 seater I'm designing now, I'm using a GM Ecotec motor and tranny, sitting sideways like it sits in a car, but mid engine driving the rear wheels. Mine is definitely off-road oriented though.

Do you know the history of that frame? It definitely looks like an old single seat race car. It would be a shame to cut it up too much and ruin that look.