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Holley 390 Tuning Tips
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Author:  Dusterski [ Wed Nov 07, 2018 10:25 am ]
Post subject:  Holley 390 Tuning Tips

Hi everyone, first off I just wanted to say thank you to everybody that has contributed to this website over the years. It has been a huge help with keeping my Duster roadworthy. I felt it would be right to contribute my own experience with using a Holley 390 on a slant 6. My cousin and I have been testing out different combinations of jets, shooters, springs, pump cams, etc. and after many months we have found a combination that really works well with this carb. Hopefully this will help some of you out there trying to fix the bogging, hesitation, flat spots while dialing in the 390. When I purchased this car a year ago it had an Eddy500 that would run awful and stall out constantly. We eventually got the 500 to run without stalling, but after checking the plugs(carbon fouled) we decided to go with the smaller 390. The Holley was a huge improvement right out of the box, but it took some tuning to get it perfect. The Duster is now a reliable daily driver. Heres our setup:

1974 Gold Duster
Engine: (to the best of our knowledge) stock 1974 225
Trans: 904
Rear: 7 1/4
Intake: Offy 4bbl
Exhaust: Hooker Super Comp headers 2 1/2 dual exhaust
NGK plugs ZFR5N
Timing 14BTDC

Holley 390 4bbl w/ vac secondaries
Yellow secondary spring
Red pump cam in #2 position
Primary jets: 56
Accel pump shooter: 31
Power Valve: 8.5

Im not sure if this setup will work for everyone but this slant 6 loves it. I hope this will help somebody out there trying to figure out the 390.

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