I’d be looking at valvetrain stability issues, and/or some EFI unhappiness.
Cam is quite small for that ci…….. but should still be more than enough to make a solid 1hp/ci.
We did a 505 a couple years ago, ez295 heads, same intake, brawler 1050 carb, 245/251-110 HR cam, made 640/640, peaked at about 5900.
The bsfc numbers on the dyno sheet are way off…….which could just be how they were reading the fuel flow with the EFI.
I don’t know what the elevation is at the dyno facility, but the sheet is showing a 7% correction(which isn’t really unusual for July)…….. so the uncorrected power was barely over 440hp.
Basically, it’s a situation where the engine is way down on peak tq……. And is never able to recover from that…….. and as a result, the hp is also low.
I agree.