earl3820

This is some info I discovered while trying to install my 4100 carb on a 66 Coupe. Manifold is the Ford 4-V dual plane with a 1" spacer and and a 41oo Autolite I rebuilt.

I have read a number of articles where people experience issues when changing out from Holleys to the 4100. What I have discovered is that every base gasket I purchased from both Mustang dealers and other stores, none of them were punched correctly to fit the 4100. I also had issues when I purchased the Felpro 60059, Felpro 1901, Victor gaskets and the ones sold by two Mustang vendors all of which are shown in their systems to fit. The typical issue was the location of the four individual bore openings causing vacuum leaks and puddled gas in the intake voids.

As an example, in all cases my idle mixture screws had to be out at four turns to idle properly. However, when the choke was active, major problems and stumbling.

I thought at first my re-build was bad. Then I made my own gaskets using the spacer as a template. Once installed the 4100 works perfectly with idle mixture screws at approximately 2 turns out. When cold also works with choke set at 2 rich setting.

All I can determine is that all the gasket manufacturers are punching the gaskets to fit a Holley pattern. This will not work.

Hope this helps those out there with similar problems.