I read the recent CC fuel pump article which states that a mechanical pump won't cut it on a 500hp engine.

I have a 383 sitting in a 1930 Model A Coupe right now that is still under construction. (The engine hasn't been started) 

Desktop Dyno estimates it at 518hp @ 6000rpm and 500lbft @4500 with the stock head flow #'s (which have been slightly ported) (I know, I know, the computer simulations arn't perfect but I'm in the ball park)

Any way, it has a Malory high flow mechanical fuel pump attached to it right now and the article has me a little concerned.

My questions are:

Didn't several factory big blocks come with mechanical fuel pumps?  ie. L88, LS6, ZL1 (add a set of headers and these mills made at or above 500hp) What gives?

Of the modern high performance mechanical pumps available, which one would come the closest to giving me what I need?

For fun, I figured I'd add the engine specs.

383 Chevrolet   Engine 

Four-bolt main block with nodular iron main caps. Bored and honed with torque plates. Plus .030, Deck squared with mains. (Total bore 4.030”)

5140    Nitrided Steel Scat crank (3.75” stroke)

4340    Forged Oliver Rods (5.7”) with 7/16 ARP cap screws. 600 H.P. rated

Manley Ready-to-Run Series forged lightweight Pistons

Speed-Pro File fit Plasma Moly 1/16, 1/16, 3/16 rings.

Crane roller cam:  HR-276-2S-12 IG

(228 / 237 @.050 & 520. / .542  W/ 1.6 Rockers)

Competition Cams retro fit roller lifters

Crane Gold 1.6-1 Roller Rockers

Ported Dart Pro One aluminum heads. 215 runner, 2.05 intake valve, 65 cc chambers.

Fel-Pro Head gasket (.041” compressed height)

True roller timing chain

Moroso 6 qt oil pan, high volume pump, windage tray.

Compression calculated at 10.8:1

Edelbrock Performer RPM Air Gap manifold

Holly 770 cfm Street Avenger Carburetor

I'd like to know also because I just bought a Holley mechanical 110 gph fuel pump and a regulator and i'd like to make sure it will support by big block like it should.