race to pump gas mix and converter stall?

I do that very thing in my 572 - 11.5-1 Hemi Cuda. Around here, the only ethanol free gas is 90 octane. The pump gas 93 octane gas has minimum 10% ethanol. I think the OP's combo would be iffy at best on 90 octane gas. Same with mine. So, I do the following:

I buy a drum of VP - 110 racing fuel and mix it in another drum 50/50 with the 90 octane ethanol free fuel. I end up with about 110 gallons of 100 octane, ethanol free fuel. Blending the VP with the ethanol free fuel really lowers the cost per gallon of the fuel. Hope this helps...

See the following octane mix calculator.

Octane Mix Calculator - Wallace Racing