4.33 is work'n engine pretty good continuosly at 70-80 mph.
Same as Bjorn, drove mine for years with a 195 stat.
RA3/th350/3.73's. Ran 210-220 all the time.
If you dont have an analzer to check air/fuel ratio, try retarding timing 4-6 degrees. See if that helps.
Or run at highway speed somewhere you can shut it off and pull over and check spark plug color.