Is a Holley 750 DP too much carb?

maybe with a egg under the gas pedal, lol
You need to learn how to tune the engine is what you need to do. Being resigned to multiple stops at the gas pump is a bad attitude to have.

The carb is probably fat on transition, IFR and IAB's.

Ignition timing is not close to good for the cam.

Had similar builds with a 750dp and got 18+mg on the highway and mid teens around town.