I'm currently running a 1.21 size. Can't get it to idle right. I have checked all of the obvious. Have a good 1.08 sitting here as I type waiting be to be installed. I think this will run much better. My 1bbl Carter ran better than the 1.21. Just my experience.
A closed mouth gains no foot.
1977 CJ5, '75 258, Motorcraft 2150 carb, HEI dizzy, BDS 2.5" suspension, 3/4" Daystar Rock Krusher Greasable shackles, M.O.R.E. steering brace, Flaming River steering shaft, Tie rod flip, Yukon AMC20 axle kit, 1.5" Trail Sport wheel spacers, 15x10" Black Cragar soft 8s w/ 33" Yokohama Geolander MTs, Goodridge SS brake lines, Classic Tube stainless hard lines, YJ power brake with front disc upgrade (had 4 wheel drums)