Slipping 5-Speed?

[JSFIRE79]

On my daily driver 91 CONV. GT , which is mostly stock, except exaust, cold air, underdrives, and maybe gears ( bought car recently and dont know) I've had really irritating times with the trans. I bought the car with a rebuilt T-5 and Lightwieght flywheel......Two months in, it was toast. I installed a Heavy Duty FRPP Clutch and pressure plate and resurfaced the flywheel cause it looked like ****.....and one month later same CR#P!!! Basically I'll be in 5th on the freeway and step on it and the RPMs go up but doesnt move the driveshaft. and the smell of burning clutch slaps you in the face........car stays in gear so it's not sliping out.......but feels like the pressure plate is just not holding the RPM.......

WHY IS THIS HAPPENING? on a stock motor one month should not wear down a HD clutch that quick....It shifts smooth it just will not hold the rpm unless I baby it up......any suggestions......???