I understand that it's a "budget crate motor", but for use on the street (IMO) it does not deliver the BIG power where a street driven vehicle could use it .
Looks to me that they used a cam that worked best with their heads, which don't seem to be working all that well .
A 540 with Dart (non-CNC-345-121) aluminum heads, 9.7 to 1 and a hydraulic roller of .630/238-.630/248 on 110 @ 106, will easily pull 690 lb-ft and 740 HP with a single 1050 carb, under 6500 . (2200 to 6400)
I build them in this manner for "outdrive boats" which cannot use RPMs above 6000 for long runs, but need all the torque they can get in the mid range . Since "torque moves the load" .
At $10K the motor is "cheap" for what you are getting, but I don't agree with where it makes it's power, for street use
If you really wanted a "street beast", I'd go with an Iron headed 496, 8-71, 2 X 850, .590/240, .590/250 on 110, flat tappet cam, and be all in for around $12,500 .
Buy a used blower and have it rebuild, spend your hard earned money on the parts and combinations that give the most power WHERE YOU NEED IT, not just on the dyno .
A 7 lbs street blower will make a 496 breath like a 744 cubic inch motor (half an atmosphere more breathing) and still have a STREET-ABLE RPM and power range .
This can also be done using 91 pump gas, if you keep the heads/cooling cold enough .
If it were me, I would build this "strong, simple, street blower motor", but run a "hat" rather than carbs .
But I'm old and I don't want people looking at me go fast, so I'll keep my turbos .