Makes sense to verify where the cam is installed. If nothing else, it resolves that question. I do believe the problem is deeper having had both a Mopar electronic vacuum advance and a MSD billet mechanical advance distributor on the motor. Also, it is worse with a mechanical secondary vs. a vacuum secondary carb. I guess that makes sense if the cam were too far advanced in that shooting more gas at snap open WOT would produce a more severe stumble or bog. I researched hemi timimg and they seem to run better with lower timing than 440's. Mopar Action ran a 426 crate motor on the dyno @ 38* and then at lower settings. They found peak power at 33*. Several comments so far point to cam timing and sloppy crate motor quality control issues.