For what its worth to all following this thread and it may sound really stupid but in my 1951 1 ton with 216 and rochester carb, I had same symptoms as described by Denny. Engine ran fine without problems until down the road 5-10 miles. Then it would start acting real funny, dieing, lack of power, backfire, ect. Thoughts of i am going to be stranded going thru my head. Pull full choke and limp on home. Check carb, plugs, points , timing,fuel filter and pump, hoses ect, no problems found, next trip, same story. Just by chance, and I can not swear that it solved the problem but I went from a 195 degree thermostat to a 180 and problem went away. I have followed this thread from page one and it seems everything else has been tried.Just for what its worth to any of you experiencing similar problems. Jerry from Minnesota