A833 + clutch question : 68 318 engine

The 143 is for something like farm truck apps with non-passenger car trannys. I've never seen a 143 in a EDIT; teener, pas-car.

I like my diaphragm clutch, but as it ages,and at cruising Rs (2200rpm), the flyweights occasionally stick, causing a slight vibration. A little Rs in neutral gets it sorted. Well, I'm assuming it's the flyweights.....
I had the stock 1970 flywheel re-balanced for my 360. It seems to have worked out just fine.

On a street teener, don't be tempted to go lightweight on the flywheel, unless you are gonna run a deep starter gear. Or unless you don't mind taking off like a Mustang; slipping the clutch out with plenty of revs. No! Show your Mopar torque with a heavy flywheel; Just dump it and go.