340 on dyno video, whats your opinion

Dyno's are subjective. Numbers can be manipulated just in the service of the dyno. Now if they started with a base run then did some changes (heads, cam, headers, intake, tune, carb) you could compare results on that dyno that day. Otherwise it's just a run and it did what it did that day. The track times will tell if it goes to one and is in a sorted car.