What thread size are Holley Jets?
1/4-32
Features: Main Jet Tap. 1/4-32 UNF Thread.
Do Holley main jets affect idle?
As far as jetting goes, the jet size will not affect idle, as the jets don’t come into play until the carb transitions to the primary circuit, unless the throttle blades are open far enough to expose the transfer slot.
What happens if my power valve is too big?
Problems: The incorrect size power valve, or a blown out power valve can cause problems such as poor fuel economy, black smoke emanating from your exhaust, dark or fouling spark plugs and a poor idle. If you suspect that your carburetor has a blown-out power valve, you can perform this simple test.
How do I know what size carb jet I have?
Consult your manual first to find the stock size. Also pay attention to the numbers on the side of your old jets, which you’ll be able to see in the steps to come. A larger jet number means a bigger hole and more fuel. A smaller jet number has smaller holes and should be used if your engine needs to run more lean.
Can you drill out carb jets?
By drilling out your stock main jet to larger sizes you will be able to narrow down what jet size your carburetor needs. You will need a numbered drill bit set. The brass main jets are easy to drill so you can get by with one of these inexpensive drill bit sets.
How many jet sizes does a power valve add?
The ratio of the amount of fuel added by the power valve will change with each version Holley carburetor, but typically the power valve circuit will add anywhere from five to eight jet sizes-worth of additional fuel.
How do I tell what size my Holley jet is?
How to Calculate Jet Sizes for a Holley Carb
- Establish the elevation and temperature the carburetor will be operating within.
- Establish the current jet size of the jets within the Holley carburetor. Adjust the jets one size for every 2,000 foot change in elevation or for every 35 degree change in temperature.