Part throttle bog then backfire?

I think you're on the wrong track, your comment about "RPM going to zero" is something THAT SHOULD NOT HAPPEN. I think you have an electrical problem that is dropping spark entirely, or losing supply voltage.

hmm, but why would it happen at part throttle? Its never occured at WOT when i would expect there to be the most load on the system.

I'll take a look at the ignition wiring tomorrow and see if i can't find anything visibly wrong back there. I know that wiring looked a little frail and ify from when we put the magnum motor in it. so maybe time to redo it or step up to an MSD distributor.

The float adjustment turned into a cluster eff and the car wont start at the moment. Awaiting some needle/seat gaskets from summit for tomorrow. :mumum: Which regardless of the resolution to this issue has put efi at the top of my to-do list. Either carbs hate me or i have the magical ability to do very little to them and make them stop working. :banghead: