I bought a kit back in the day, Precision I believe. Not too sure on what Black dragon uses. The door seals and hatch seals aren't the greatest but everything else fit pretty good. I've replaced the doors with kia sportage ones. I've still get a different hatch one.
I looked on ebay and found universal kits, in the size I needed, with a few 90,45,30,0 degree bends. Also might need different couplers. Yes, some cutting was required but turned out pretty good.
Worst case is would be you need to get a different collar length to fit the pressure plate.
I do see now that centerforce does have a seperate bearing for 70-74(probably compensates for the height difference), but it really depends on the collar length you have.
Could try advance auto parts. http://shop.advanceautoparts.com/webapp/wcs/stores/servlet/product_Brake-Master-Cylinder-Cardone_5804256-P_230_R%7CGRPBRHYAMS_727899857___
So did this happen out of the blue or did it always do this? Could be the ka tps as the L tps is a throttle position switch not a sensor. Also if the harness is a 81 with a resistor pack and you're using an 82-83 ecu with resistors built in, it could cause problems.
Another idea could be close off the upper triangular portion, than have the doors open up like a mouth. The upper portion could be gas shock supported and open upwards and the lower portion could be "rampish" when lowered.