I think a good street-lobe solid roller could add a bunch of power. I don’t think he needs 20 more degrees to get there if everything else is right. That said, It’s not clear to me what the OPs budget is and if converting to a roller is in it.
Also, like someone else said, even with another 50 hp, he’s s still at 11.0s at 122-123 mph.
Seems like maybe it’s more than the cam holding it back, like others mentioned too. Converter, fuel, collapsed muffler….
It might be helpful if the OP posted some time slips and corresponding DAs for the runs for folks to look and to see if it makes sense or something pops-out.