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a miss

1355 Views 8 Replies 7 Participants Last post by  FEandGoingBroke
I've been tuning my Holley 4777. I'm running quick fuel metering blocks. I've the Idle feed restrictors dialed in and it runs best with 40IFR's. All was good untill I put my new flowmasters on and now I have a miss at highway cruise speed (65mph @ 3100RPM) I can speed up a little and it will go away, if I back down it misses all the way to about 1500rpm. Do you think its jetting (71 prime 81 sec), timing, or need to increase the IFR's again. Like I said this started after the new mufflers.
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freeing up the exhaust will tend to make the fuel mixture (carb) go lean. If the carb was "dialed-in", then I suspect it to be lean now.

does this happen all the time, some of the time?
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