Another Super Victor?
I'm not an expert, but here's my thoughts.
I was surprised that you have 4.00" crank, after you wrote: "there's not much under 3500rpm". So i think your camshaft must be at least 260°+ @.050", and power range starts at around 3500rpm, and doesn't "work properly" under ~3500rpm. And replacing the intake, it doesn't help much JMO.
560Hp, what rpm??
Auto or manual, if auto, what torque converter and stall?? Bad/wrong converter kills the whole combination...
And what carb, down-leg booster or annular booster?