I had this problem ... it was misalignment between my Lakewood scattesrshield and the crank center line. Hopefully, the OPs problem is a simple clutch linkage adjustment for more air gap when the pedal is pressed all the way down. I measured runout when I installed it and it was like 0.016 total (.008 off). I couldn't get the runout below 0.010". It would be 0.008" runout and then I'd tighten the bolts a bit and the runout would grow to 0.014" or more. I'd hit it with a deadblow hammer to try to get it closer but then it would still walk out as I tightened it. I got it as close as I could and welded the dowel alignment bushings onto the scattershield. I thought I could live with it but it dragged and made shifting into first from neutral difficult. I could tell that the cluster was spinning with too much drag when I tried to put it into 1st. It would finally crunch in as I pressed the shifter forward and I'd take off. I finally decided that the 30 yr old bellhousing needed to be retired so I switched to a Quicktime. The pilot bushing was way shot when I took it apart. The Quicktime indicated at 0.002" total runout right out of the box which made me happy. But after just a little bit of driving, the clutch fork pivot bracket folded over and I had to limp home. I think that everyone but me must be running a hydraulic throwout bearing by now but I didn't want to fix what wasn't broken (linkage) and I didn't have another $700 to throw at it. My family is giving me this Sunday off so I hope to bolt it all back together and get it down off the jackstands. Stay tuned ...

I do use the Pennzoil "Synchromesh" NON synthetic gear oil and that has always worked well over the 40+ years that I've been driving a 18 spline 833.