New Clutch 'NO' Difference

[Xterminator03]

I got a king cobra clutch installed on my stang (89 GT)
On the Street it is great. Off the line it's Magic
But when i go for long drives on the highway and then drive on the street the clutch feels like is is sliping. It feels like an old worn out clutch. But when i turn the car off and let it cool down for about 20-30 minutes the clutch feels good again. what the hell is the problem.
-Could it be that I need a new Clutch Quadrent.
-One friend suggested it could be the trow out bearing but a new one was installed when with lutch as well and pressure plate.
Please help

 

[giddyup306]

My guess would be that your clutch is getting contaminated somehow. I've seen cars where when they were driven for a while coolant would leak onto the clutch and cause a slipping situation. Did you happen to notice any wierd residue on the clutch when you removed it?

 

[Xterminator03]

When the old clutch was removed it did not have any contamination just regular wear