The issue with putting a big motor in the back is the weight balance - a couple of guys have done it and apparently the handling suffers alot. A mid-mounted motor where the back seat is, gives the car nearly 50/50 weight distribution. There was actually a couple of companies back in the 60's/70's that did mid-engine conversions - Crown and Kelmark - but the parts are long gone and nobody still makes them. Still, not a bad project to try one day
