422 dyno fail

If anyone is interested, here's the dyno sheet along with what I know about this motor. Dyno session was run with fresh plugs and oil change.

340 blueprinted and balanced. .30 over. TRW flat top pistons. Mopar steel crank, Mopar performance rods. ARP fastners. Holley Sniper EFI with Hyperspark distributor. Edlebrock aluminum heads. Weiand Stealth dual plane Intake. Competition cams hydraulic roller cam. 490/490 lift, 262 duration. 10.5-1 CR. MSD Blaster SS coil. MSD 6AL ignition. 8mm plug Wires. Aluminum radiator. 6-Blade aluminum cooling fan. Hooker ceramic coated long tube headers with X crossover. 2.5” Pypes Turbo mufflers. Vibrant Ultra quiet resonators.
Trade in those Turbo muffs for some straight pass thru mufflers and you will see a noticeable increase in HP.