hello I had a 83 jeep Laredo dropped off for popping out the carb under a load.the customer put a 85 4.2 with weber carb and gm style distributor.so I compression tested 155 all cylinders,set timing tdc compression #1 all timing marks lined up and rotor pointed to #1,firing order is correct,plugs good,smoke tested found leaks at carb adapter plates replaced re tested checked good,set timing at 9degrees btc and idle 650 as book states,still popping only under load ,swapped carb with a known good one same thing,messed with distributor timing could not get it to stop popping so put back to stock specs,choke is fully open,electric fuel pump has good pressure,so sitting idles perfect can get it to pop sometimes hitting throttle fast not always.but when you try to drive it pops through carb and falls on its face.i am not sure wich direction to go now so I am hoping a jeep expert or someone here can point me in the right direction.thank you for any help/ideas