[Fot] Fuel issue

[Andrew Devenish]

Guys, 
          My car ( 1300, 12.5:1 comp on Sunoco 110 race gas, dual HS4 ) is still giving me grief. I’ve chased all the things I can think of, but still same problem. It starts and runs great, but after a few laps of the yard ( 5-6, only 1000ft  or so per up/down lap, so quick accels then braking to turn ) it goes very lean ( I have O2 sensor ) and stops. I’m running it without the hood for these test runs. It always stops at the entry to a turn. 
         I’ve been working on it a lot, so know it has fuel pressure, and the float bowls are full of fuel. All plugs look very similar. The needles (AAA) are the spring type, and the slides move freely. I use ATF as fluid, but have tried 50 weight too.
        After a minute or so it will fire back up, but only run enough to get back to the shop before going lean again. If I pull out the choke it will run, but is unstable. 
       I have wrapped headers and a heat shield around the carbs but they do still get hot.

       Any ideas ?  Thinking to try some less volatile fuel as it seems heat related and the Sunoco evaporates so fast !
     

Thank you, 
      Andrew Devenish

Sent from my iPad
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