Should I be feeling more power?

Hello all:

New member here and happy to belong to this forum!

I recently acquired a 1972 Duster 340. It’s a beautiful car in fantastic condition. Nearly everything has been “redone” and the motor is a built 340. I don’t know “jack” about motors and the specifics related to HP and torque, but I feel that this car should be “pulling” more through 2nd gear. Here are the motor’s “specifics”:

• Correct Vintage 340 block bored .030 over.
• TRW forged pistons & Speed Pro Piston Rings-Compression 11:1
• Mopar Performance Purple Shaft Cam P4120235
• Performance Electronic Ignition with chrome box and Accel Super Coit
• 340 heads rebuilt with new Valves, hardened valve seats and 3 angle vale job
• Hooker Comp Headers with Jet Hot coating mated to 2.5" exhaust with cross pipe and Flowmaster Mufflers
• Holley 750 Carb atop Edelbrock Torker I| Intake manifold with K&N Air Filter
• Mechanical Holley Fuel Pump on engine as well as secondary Holley Electric
  Fuel pump located near fuel tank and operated by switch in cabin
• 3 row radiator with overflow bottle and Mopar Performance Viscous

When I punch it from a stop, it initially really wants to go. Once 2nd gear kicks in, the rpm/torque seem to plateau. Once in second, torque seems to diminish and it takes a few seconds (after shifting into 2nd gear) to start gaining more power. I’m not sure if my description makes any sense, but it’s the best I can describe.

Do you think it simply needs a tune up? It’s been roughly 1,500-2,000 miles since the last tune up/oil change. Everything motor-related, including transmission, has recently been rebuilt. Supposedly, all drivetrain components from front to back as well as suspension and electrical additions were rebuilt and/or installed by the Montgomery Race Team. Currently the engine and transmission have roughly 10,000 trouble free mites since their rebuilds. Drivetrain(Engine, trans, rear and suspension) was rebuilt and installed by noted Mopar Super Stock factory backed Mopar racer Ken Montgomery Sr. (verification available from the family if requested). Has been maintained by the same family as well.

Any insight regarding this post would be greatly appreciated!