[jhv48]

I too have been having a battle with my clutch.

After many man hours and $$$$ spent chasing the problem, it finally boiled down (literally) to a heat problem and the push rod from the slave not pushing in a straight line. Once the push rod was straightened (a new slave mounting bracket was fabricated) then I had to deal with the heat problem. The car shifted beautifully when cold, or while moving. When stuck in traffic in the summer temps, it would become impossible to find reverse without grinding and puting into first at a stop became very difficult.
I had to fab some heat shields for the clutch lines and switched to wilwood high temp brake fluid. I also found that bleeding the system every 6 months helped eliminate the problem.

So, my recommendations are:
1. Make sure push/pull rod on slave cylinder is moving in a straight line.
2. Use heat shields as much as possible to shield the lines from engine heat.
3. Use wilwood high temp fluid (boiling point around 570 degrees whereas normal fluid is in the 300's).
4. Bleed the system twice a year.

Took me two years of trial and error and $$$$ to fix mine. Hope this works for you.