[ab_mach1]

I would think if the clutch was getting over-powered (slipping), you would be able to get it in gear okay. You would notice it slipping or loosing power at WOT if it was not gripping the flywheel. I think your clutch cable needs more adjusting. Go in the direction where the TOB is getting closer to the pressure plate. I can't remember which way to go with the firewall adjuster to do that lol. I think this, because your clutch might not be going in enough to release it enough to go into gear at high RPM's. I have the same cable/firewall adjuster/quadrant setup. You could also check the alignment of the cable in the quadrant compared to where it's going through the firewall. Make sure it's not moving out of alignment as you romp the pedal to the floor when shifting hard. I'm no expert, but this is what I'd check if I had this issue on mine.