Ultra Street Avenger 670cfm jetting

[BruceSnyder]

I bought the carb from Summit Racing. I contacted Holley. They told me the 63 primary and 73 secondary jets is stock for the Ultra Street Avenger 670cfm. No sure why they do that. Although, my engine is running great with the 68 primary.

[lovehamr]

Originally Posted by BruceSnyder

I contacted Holley. They told me the 63 primary and 73 secondary jets is stock for the Ultra Street Avenger 670cfm. No sure why they do that.

It's Holley. If you called back today and spoke to a different person you'd likely get a different answer.

[Texasdoc]

I have the 670 Street Avenger. I also bought mine from Summit. However, it was really messed up. Definately someone had bought it and returned it. The secondaries were opened significantly and the primaries closed. Before I figured out how to tune the carb, I couldn't get the idle below 1500.

Mine came with 65 primaries and 68 secondaries. I switched the primaries to 68 and the secondaries to 78. It runs much better now. Before, when it was hot, it would stumble at approx 2500-3k rpm. I don't have an Air-Fuel meter, so not sure exactly where it was.

Edit: Oops, sorry, I have the Steet Avenger, not the Ultra. Not sure was the differences in jetting between the SA and the Ultra is supposed to be.

[70mach123]

I just had an issue with my 670 Ultra where the factory incorrectly put the 63's in the secondary's and the 73's in the primary's!!! It was bogging when my 351C hit 3rd and 4th. Holley gratiously gave me a new set of bowl gaskets. I then opted for a pair of 68's in the front and stayed with the 73's in the back. All is now good, what a pain though. worth double checking if your new one is acting up. Be sure to have new gaskets, these bowl gaskets are good once. Part # 108-83-2