The manual MKIII's weighed about as much as our A bodies (3000-3400 lbs). The automatic versions weighed (3500-4000 lbs). Anyways, you're about right where the transmissions can only hold about +/- 500hp.
Here's a swap link...
http://board.moparts.org/ubbthreads/showflat.php?Cat=0&Number=3168502&page=0&fpart=all&vc=1
