Yep, you need a 1.08 carb. The venturi size and jet size are not the same thing. You need a 1.08 and probably somewhere around 46-48 jets depending on your elevation. The 1.08 carbs came on 6 cylinders and small V8's (mine on my green Jeep was off of a 289 equipped mustang).
The 1.21's came on 351's and other larger V8's. You can put small jets in there to try to compensate for the larger venturi, but it won't every really be able to be properly tuned. Best bet is to find a 1.08 carb and sell the one you have.
85 CJ7 258, borla header, Team Rush, MC2100 ,optima batt, Warn 8274, agr super box 2 & pump, T5 w/ B&M shifter, centerforce 2, superior 1 piece axles, warn hubs 2.5 in lift, 31" BFG MT
85 CJ7 258, A/C, T176, MC2100, Team Rush, Warn XD8000i, superwinch hubs, 3in lift 31" BFG AT/KO