I'm starting work again on our '87. It has trouble staying at 65mph and drops down to 50 mph on hills. It has 235x75x15" tires and 3.54/3.55 gears.
I've removed all of the emissions stuff, Nuttered it, replaced the entire exhaust system and did a Team Rush upgrade. Also tried running an MC2100 but it was running too rich so I took it off and put the old Carter back on and rebuilt it. I live above 4500 feet and set the timing to 8 BTDC. Anything higher and it pings like crazy. It starts fine and will rev to 4000 (but I don't like doing that because it sounds horrible). It will toodle around town all day long without breaking a sweat. But shift it into 5th and blah, it just has no power. I'd run it in 4th but doing 80 in 4th gear, well the RPM's are just way to high.
Anyway, the highway speeds out here are 75mph but everyone does 80. Who here can run 75 - 80mph in their carb'd Jeep that has limited modifications (i.e no 4.0 head)?