Barry is always better at stating things more diplomatically. I have neglected to say "Nice engine" and I apologize for that. It is a nice piece and I'm sure your customer will be pleased with it.
A lot of us have been playing with FE's long enough to have used pretty much every head/intake/displacement combination out there at least once. I was able to predict your hp peak rpm by 100 rpm (I said 6200), when you posted your cam specs on one of the other threads. It's because there are certain "trends" with different parts and combinations.
I would encourage you to look through the dyno results section of Jay's forum and see what the trends are for a 700 hp engine. There are 4 right off the bat that I see....
1. Jay's 511 combination, with 350/265 cfm Edelbrock heads, "heavily ported" Victor intake, with a 266/272 @ .050" solid roller camshaft. It made 706 hp @ 6400 rpm with 636 lb-ft at around 5000 rpm. 11.75:1 compression.
2. Tim Meyer's 511 combination, with ~360 cfm CNC ported BBM heads, a BBM Tunnel Wedge, and a Bullet solid roller. I was involved in the camshaft selection for that one, but I can't recall the specs off hand....I would imagine 260's/270's. It made 700 hp @ 6700 and about 625 lb-ft at around 5000 rpm.
3. My 465 cubic inch Tunnel Port, with ~370 cfm hand ported Tunnel Port heads, a 2x4 Tunnel Port single plane intake, and a solid roller 260/270 @ .050" with .740" lift, 12:1 compression. It made 696 hp @ 7000, with 588 lb-ft of torque.
4. My 512 cubic inch Tunnel Port, with ~370 cfm hand ported Tunnel Port heads, a 2x4 Tunnel Port single plane intake, and a solid flat tappet 270/280 @ .050", with about .630" lift. It made 723 hp @ 7000 with 657 lb-ft @ 4500.
All of those engines were very specifically built, with basically all custom parts, some featuring some very specialized porting, custom camshafts, etc. All but one was race gas oriented.
For someone to come up with a 6300 rpm peak 482 with out of the box 310 cfm heads that backup at .600" lift, along with a shelf cam, pump gas, etc., it just doesn't "jive". Your 650 hp guess was maybe a tad optimistic, but not really unrealistic. 700 hp is unrealistic.