Is there a kit sold for tuning a Holley carb that includes different sizes of jets, etc? Specifically a 4160 Vac Sec. I checked Summit but didn't find much. Also how do you know how thick of carb spacer to use? Thanks.

 

They have a kit that's really expensive and has WAY more than you need. Get the vacuum secondary spring assortment kit, and the accelerator pump cam assortment kit for starters. Then get larger/smaller jets/squirters etc as needed. It'll be cheaper then getting the big kit, which has most of the jets in it(95% of which you don't need).

Spacer tuning depends on the engine, sometimes they make more power with, sometimes without. Best way to determine size is go to a drag strip, drive it exactly the same way and try different spacers/tunes. Whatever gives the fastest mph is the right one.

 

I see my 4160 comes with a size 64 main jet. If I were to buy a few different sizes right now without knowing what ones I needed, should I buy a 65 and 66 or should I get a 63 and a 65?