Cascade Crew

nonsensekid20 · Posted: Sat Jan 14, 2012 1:46 pm Post subject: Still a flat spot

Holley Street Avenger 670cfm and the car still has a flat spot. When I hit the gas it should go zoom, not, hesitate, then zoom. Any ideas?

Alphius · Posted: Sat Jan 14, 2012 2:17 pm Post subject:

Too bad you got rid of the fuel injection. Embarassed

I'm guessing you have vacuum secondaries on that carb.

Check this out, it's a pretty concise Holley tuning guide. I had to tune in a Holley 600 on my Mom's Chevelle, it's not that hard once you get a vacuum gauge and figure out what each circuit in the carb affects. I think you should pay particular attention to Part6.

http://www.angelfire.com/fl4/pontiacdude428/HolleyInfo2.html

aaron_sK · Posted: Sat Jan 14, 2012 6:57 pm Post subject:

Make sure the pump cam is properly adjusted. The slightest bit of lag in it will cause a huge bog. It can and will come out of adjustment. Iv;e had it happen.

Make sure your pump shooter is big enough.

Most Holley's have too low of a primary PV from the factory IMHO. You need to run one a couple inches under idle vacuum, and most carbs come with like a five or six. Rolling Eyes

Make sure you have enough initial timing. If you have your dist. set up with low mechanical and a lot of vacuum and you step on it the timing will drop and it will seem like a Holley bog.