Believe Brett did one that made more than that.Good bit more.
The 376 inch motor I posted on here that made 737 and won his class made 737 in North Carolina and made 770+ in his testing prior to the competition.
should be noted he had to run mufflers during the competition, and the room where the pulls were made was open to the outside. Humid 90 degree day.
That motor only had a 255@50 roller, and was under 12 to 1
He told me( local to me and does my stuff, Jack at Valley performance) he could make 800 without working up a sweat if he didn’t have to follow guidelines the dyno competition mandated. More cam, more squeeze, more inches, etc.
He really likes the heads