you said: "The misfiring sounds like a rev limiter.". I experienced the same when reving my engine under load. Car didn't rev. Turned out to be a clogged fuel filter in the primary inlet (the small brass filters inside the holley fuel inlet). Get rid of them, and check your external fuel filter, if any, and your fuel pick up. It very much sounds like engine is not getting enough fuel at high revs and load.
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