Welcome to the site from Houston. Cool car! I'm surprised you find the gearing to be tall. Are you sure its a 3.42? I really like this rpm calculator....
http://www.csgnetwork.com/multirpmcalc.html
Use the bottom section so you can plug in your overdrive ratio.
According to it, a 25.6" tall tire with a 3.42 rear gear and a .63 overdrive should turn 1838 RPM at 65 and around 2404 RPM at 85. That doesn't seem that tall to me which is why I ask if you are sure it is a 3.42. I don't doubt its an 8.5 but who knows if the gearset has been changed. Maybe a 3.08?
Is the identification tag still on the trans? If you can identify the transmission for certain (thereby identifying the gear ratios) and confirm the rear axle ratio (jack up rear end and see how many turns of the driveshaft = one turn of the rear wheel - will be close enough to tell if it is 3.42 or something else) that will help in identifying what change to make to get the car more to your liking.
The clutch desperately needs to be replaced. It wasn’t apparent immediately because I babied it the 200+ miles home from where I bought it. I cranked on it and did some drifting and donuts in a parking lot for my 8 year old son. That pretty much fried whatever was left of the clutch plate. Hahahaa. So maybe the bad clutch makes it seem geared tall. A new clutch kit is first on my list but it’ll be months before I’m able to get to it. I bet that’ll make all the difference. If not, maybe 4.10s is where I need to be. 👍🏽