High altitude jets for BFN Carb

Calling JQ!

What's the number stamped on the secondary metering plate?.

It'll be a 2 1 or 2 digit number like a 7 or a 10 or a 12 or any of about 40 or so different numbers.

From that number you can determine the main hole size and the idle hole size.

Bonus question:

Do you think I'll need to change the accelerator pump cams and power valves too (for 6,000ft operation)?

As KENO suggests, you may want to call the Holley help-line with your carb model and/or serial number. They can likely tell you what the stock configuration was.

I would look at dropping 2 to 3 jet sizes. Jets are cheap, so you can buy both. Start at 2 sizes down and see how things feel. Listen for knocking or detonation. Read your plugs after a couple of hours. If the mixture still looks a bit rich, then swap out to the next size down.

You are correct that the Holley 4160 has no replaceable jets in the secondary, but rather a change-out of the secondary metering block. (This is why I like the QuickFuel carbs as both primary and secondary metering blocks have changeable jets as well as air bleeds) I know folks that have drilled-out the secondary block, but I would recommend caution, as you can't go back if you drill too big. Also, since you are looking to go leaner for altitude, then drilling out the secondary block really isn't an option.

JQ

Im also running a 454 here at jordanelle res. Im not sure on the jetting because I run an edelbrock carb, But i can tell you I set my timing exactly at 10 degrees and it runs fantastic. It advances to about 32 total and it runs perfect.