I have a 51 ford truck,all stock. I have been chasing an issue with backfiring and poor running under heavier throttle. Since I got the truck I have replaced the tank, fuel pump,stock carb with a national carburetor rebuilt unit, plugs, points,etc. The power valve in that carb started leaking,so I replaced it. Went through the same issues everyone else had with incorrect valves, finally got a 7.5 inhg installed. Still having the same issue. Checked points, replaced vaccum advance,no vaccum leaks can be found. Runs 17 in hg of vaccum at idle. I feel like I still have a power valve issue. I went through the carb with a kit from mike's carburetor parts when I replaced the power valve. Do I need a different rated valve?
