VE% is a hard one to estimate without a very expensive dynamotor and measuring equipment, so make SWAG! For reference, Holley says, “Many high performance engines reach 100%. You need to know the size of the motor, CID, the maximum RPM you intend to run your engine and the VE% (Volumetric Efficiency Percent). For this reason I will just introduce the formula and comments that Holley has in their web site, make my recommendation and let you figure it out. If you tell someone that their 302 CID engine with the 700 CFM carburetor would run better with a smaller one, look out. Carburetor size can be a very emotional status symbol. Good calibration requires the proper carburetor size for your engine, and more is not better. I recommend that you use the reusable blue foam type gaskets.īefore you start, take note any specific problems you may be having like fuel leakage, black smoke, surging, lack of power, hesitation, erratic idle speed or poor idle quality. The carburetor can remain and metering bodies several times. Hopefully, you are familiar with the Holley and it is clean or recently rebuilt with a Holley kit. In order to calibrate the carburetor to your engine, the engine must be in reasonably good shape with a properly timed distributor, no vacuum leaks and clean fuel and air filters. Many of you are Holley experts and have better methods than what you will read here, so please write in and describe them. and You may want to go to them for more complete information. I have refreshed my own experience with information from the following web sites. Part II will cover the power valve, vacuum secondary, the accelerator pump and flooding problems.
I will discuss carburetor size, describe how to set float levels, adjust idle and select the main jets. Since most of us don’t have a flow bench with a lot of specialized instrumentation, I will describe back yard methods using common mechanics tools, a vacuum gauge, eyes, ears and a sensitive butt. In this article I will describe what modifications are available for a generic 4150/4160 Holley four barrel. The Holley carburetor can be calibrated to the engine for optimum fuel economy and performance. This section addresses how to select the correct carb for your application, demonstrate the steps for calibration, show how to set the floats and adjust the idle mixture and speed. By John Logan in the May and June 2006 RootesReview: Part I