what did he do? simply remove the choke plate but leave the tall horn that holds the choke plate?

if that's all he did, then no, I don't think he gained any hp. maybe 2 or 3 from less turbulence through the venturies in the carb.

if it's a carb that was designed without a choke like a 750HP that was fabricated without a choke, it might make 10-15 hp more? Has anyone done a back to back dyno test to show the difference here? It'd be neat to see, a mechanical secondary 750 holley with a choke hooked up and working, and a mechanical secondary 750 holley without a choke.