Heim joints, are you serious? This is what I hate about this time of year, the crazy ideas that are so far off the class intent. The only shifter issues anybody ever had are VERY easy and VERY cheap to fix and are well documented online but you want to swing for the fences and reinvent the wheel. We have been racing for years with the stock setup with very few issues. Shoot, twice this year when I had clutch hydraulic issues I ran races without the clutch pedal and made every upshift and down without issue. If you maintain the stock stuff and fix what's worn and still miss a lot of shifts, it's you!
Every car that I know personally has a rebuilt or replaced motor but only one that replaced a trans because of a failure so what's the ratio, 10 to 1, 20/1? Trannies( not you Steve) are not scarce, picknpull sells them for $150. There's always a couple cars there. If you're pulling fenders or other things, crawl underneath and pull the trans and stash it in the truck for a spare.
No offense Joe but you're telling us how bad our cars shift but you have yet to race yours. When you make it out I think you'll find just how fun these old cars are! As is! I appreciate that you want to make things better but your ideas are not free, not within everybody's means, and not needed.
I go through a couple cv joints a year, how about allowing custom u joints with chromoly axles? Or for engine reliability how about dry sumps?