I recently put an old Holley 4160 650cfm Carb on my F100, due to the constant problems I was having out of the motorcraft 2bbl. I am going to soak the Carb and rebuild it and I was wondering what jet size I should use. Its going in a 78 F100 with a stock 302 with 340,000 miles on it. Thanks.

 

No one can tell you what size you're going to need. Altitude, air cleaner type, emissions setup, ring wear, along with a host of other factors will affect your ideal jet size. It's going to be trial and error on your part.

 

Can you give me a good size to start? It has no emissions mods on it and im running a spectre filter about 2in. tall and 5in. in diameter. Altitude here is around 2000* i think. I have no experience with jets, this is my first go at a holley.

 

I think the Holley 4160 models came stock with 61. You might want to try that, but at 2K feet, mebbe a 58 - 59.

As Devino246 mentioned - trial and error.

 

It largely depends on your power valve.

 

Try calling the Holly tech line .
You shouldn't go too lean .

 

My mistake - stock jet size for a 4160 is a 68 but I'm runnin' a little bigger, and at 500 feet. Please excuse.

The best idea was mentioned by 410 Highboy - call Holley.