67 428 2-4 Holleys - Jet Size Primaries?

[Mike James]

Having a problem with my car running too lean.  What jet size should I use in the primaries?

[67_1183]

Primary is listed as 66.

[Mike James]

Thank you.  I'd that what most people are running

[Mike James]

I meant is that what you are running? Others chime on what jets you are using.

[JWH]

Here is a link to the Ford Technical Service Bulletin (TSB) published in 1964 concerning the Holley carbs. If you are at sea level, start with #66 jets. I have read for every 2,000 feet of elevation, reduce the jets two sizes, so if you are in Denver for instance, start with 62s.
      Before you take the time to change jets, make certain the floats are set correctly.

http://www.427galaxieregistry.com/1964tsb.html

Jeff

[shelbydoug]

Stock jets. They're fine.

[1967 eight barrel]

If you made cam changes stock jets aren't going to get it done. You'll likely have to change the secondary plates and power valves with decreased vacuum signal and the rear plates for fuel demand in the upper RPM range, as it will likely lean out.

                                                                                            -Keith