General AFR Guidance (Holley Tuning)

mopowers said

Thanks for the input. Now, I just need the rain to go away to give me some tuning time. I've read online about a ton of folks having the same lean stumble on their Street Avenger cards. Seems to be common that these things run really lean. I'll post up results when i get a chance to mess with it.

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I'm running a 570 Street Avenger on my Ford 289, and I pin drilled the primary IFRs about .002 larger, and jetted up the primaries from 54 to 60! The secondaries were 65, and I jetted them down to 59. I used my Innovate wideband to help, but like many have said, it's only to justify the seat of your pants. Mine cruises just a bit fat on the freeway now (high 13s), but if I lean out the main jets even one step, I get a stumble. With the stock 54 primaries, my AFRs were in the mid-16s going down the freeway, and my 289 just won't tolerate that; it was surging pretty badly.

It might just be my opinion, but people talk a lot about accelerator pump tuning, but with my experience in Holleys lately, if you have a stumble from light to mid throttle, it's often in the idle or main circuit.