Well, let's look at the basics here.

Clutch fan or mechanical fan? Proven 30-HP loss at 5,000 RPM with a mechanical fan, near 6,000 RPM, probably quiet a bit more. If it doesn't have a fan clutch, that's the easiest power you'll make right now.

Get rid of the mechanical fuel pump, you paid -big money- to stroke the wedge to 493ci and purchase aluminum heads, a simple Walbro 255 with an Aeromotive regulator / return line will support more power than the block is capable of. That's a premium OEM pump and cost around $100. You'll never have a pressure drop and it will remove vapor lock related issues.

Mechanical water pumps don't draw that much power through parasitic drag, very slight decrease over running an expensive, failure prone electric water pump.

Sidewinder heads flow around 250 - CFM @ .500" lift (ootb, 270 - CFM with bowl work), which can support well over 500 - HP, but the MPH shows you aren't making anywhere near that. New Challenger Scat Pack weighs 4,400 lbs with driver. They run 115 MPH in the quarter with around 430 RWHP.

Your combination is mismatched, 30" drag radial, 4.10 gears, 4,000 (guess) 9.5" converter, 2" headers, 496-cubes, dual-plane intake (Indy, known for core shift), .519" flat-tappet (real lazy) camshaft, with heads that flow 270-CFM @ .500" lift (after bowl work).

This is begging for a single-plane intake (with a lot of port volume) and a SFT / Roller camshaft. You're leaving so much power on the table, this should be making enough power to be a low-11 / high-10 second D100.