A 4V and intake will help a lot. On the AMC 258 no more than 500 cfm is recommended. On the 292 a 600 cfm might work fine. A 600 will work on an AMC 258, but it's a bit much for a mild engine. It will load up a bit at idle and low speeds. For a full race engine a 600 on a 258 is workable. For a good compromise between economy and power the Jeep guys like the Holley 390. The Truck Avenger 470 is a popular power carb for the 258, just under 500 cfm. That might prove a good economy/power balance for the 292.
If you're handy with a welder it wouldn't be hard to make a steel intake for three side draft webers or motorcycle carbs. The cost of the carbs could get to be a bit much though!