You failed to mention the carb type and distributor...If not tuned properly, will cause performance issues. Timing should be all in by 3000 or so but it's a personal preference. The gears are fine with that trans...IMO
As well, what compression are you running?
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1967 Starlight black PMD Engineering 400 Auto 1968 Alpine Blue 400 4 speed 1968 Verdoro Green 400 HO 4 speed 2013 1LE 2SS/RS Inferno Orange Camaro.