The Euro tarmac classic rally guys, in their old Mk2 Ford Escorts, are mounting the Focus/volvo 5cylinder turbo motor in a north south config, and mating tnese to sequential 6 speed boxes, and 5.1 ratio diffs, using 13 x8" rims with open grooved slicks. Wild bits of kit, some are putting out 400hp at flywheel.
One of these hybrid things in a Mk1 Escort shell ran at the 2011 Alpine rally.
Dunno who or what makes the box, but it would have to be half eay close to what you're trying to achieve.
I do not tbink thay have a high enough torque rating
Have a look at the National Sports Sedan forums, some of those guys are into the big units