After thinking over every thing I've done I realized that I had NOT run the truck after I did the initial valve adjustment which was done after "normalizing". The backfiring didn't appear until After I adjusted the valves. I'm thinking that if it ran before albeit down on power but with out backfiring why won't it run now. I did a quick cold ck on an exhaust valve That I had adjusted hot to .013 and I could not get the feeler guage inserted. I may have a distributor problem, but I'm thinking about doing a cold valve adjustment in the neightborhood of .009 intake and .018 ex ( I had set them .006 in .013 ex). The rockers all move smoothly and I did soak all the valve stems with tranny fluid after I did the adjustment. I do have another distributor out of a 235 that ran fine before I pulled the motor out of my old 50, but I want to settle the valve question first. I'm basing my guess on cold adj on just a guess, so Please express yourselves.
Dave