Holley/Demon Carb stumble

When my friends GTO was still a bracket car he ran a ported 3310 I did for him.

He was bracket racing and wanted it to be as fool proof as possible.
He had a 4800 converter, and you could pretty much do whatever you wanted for a launch technique and it would be 100% stumble free.
He got to where he was basically “stomping” on the gas pedal.

We were playing around looking for some ET one day, so I put my ported annular 850 on it.
I had it working just how I wanted on my car, so I wasn’t going mess around with it much.
With him driving it, it had a very slight bog on the line..... and ended up ET’ing the same as with his carb, but was up about 1.5-2mph.

I drive it with a little lighter touch on the starting line....... which proved to be worth a solid tenth...... and it still ran the same speed he did.
I even instructed him how to do it...... he just couldn’t get the knack of it...... well, at least with only a few test passes he couldn’t.
I just drove it the same way I always did........ no problemo.

Basically, he stomped on it....... I quickly depressed the gas pedal.