Please don't take it that were picking on you, but this kinda topic has been covered ALOT on most RX-7 websites.
If it were easy or cheap everyone would do it.
We just don't wanna see you blow-up a perfectly good motor.
So save up and build a drivetrain you can swap right into that 'vert.
There quite a few people on RX7Club.com - Powered by vBulletin that have done a TII powered 'Vert.
With some time and money you can have that 400 hp car you dream of.