Ive noticed that when driving my dart, that above or around 4500 RPM I get this flat spot or bog. If i hit the bog, drop 250 or so RPM and then punch it again, it will climb up to 5000rpm no problems. Im thinking it could possibly be an ignition problem (missfire?). I dont belive it is detonation by the sound b/c it is more of a flat missfire type sound then a sharp detonation sound? Any help would be greatly appreciated!

What sort of ignition is it running, and what kind of carb?

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"Mad Scientist" Matt Cramer
'66 Dart - turbocharged 225
My blog - Mad Scientist Matt's Lair

You could be emptying the float bowl...

When you drop back, it gets a chance to refill

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

Im running a brand new GM hei module from a 350/350 crate engine with a Chrysler stocker-type coil ( the coil is one of my first ideas for possible cause). The carburator is a holley 600dp with a holley blue pump set at 5.5psi. Offenhauser intake. K1/Wiseco 10.5:1 engine.