Information on fuel standoff ?

[rockerarm]

I do not have access to my original "How to Hotrod VW Engines" but I believe there was some writings on the subject of fuel standoff above the stock VW carb. From what I remember, it stated something like if a low profile air filter is installed, this fuel standoff is forced down into the throat and upset/disturbs the metering of the carb. Can anyone verify, dispute, or give additional info on this? Facts and opinions appreciated.
My reason for the query is I have a friend with a '74 stock ghia but has an aftermarket chrome air filter that's top is 2" above the air horn. It has a cheap piece of foam as its element. While looking in the Wix master filter catalog, I may be able to get a paper element from 2" up to nearly 5" tall. An early stock OEM oil bath filter won't fit as the deck lid hits. Prior owner must have had dual carbs as the pedestal has been cut away. I will probably check gas mileage prior and after to determine any improvement.
I was looking at my "Without Guesswork" VW spec book and the jetting is not that different between a '71 bug which had an oil bath a/f and had a long tube above the air horn, the '74 bug with the paper a/f housing with no tube above the air horn, and the '71 bus/ghia which had the rubber elbow/tube leading to the a/f housing.
Thanks in advance, Bill

[slalombuggy]

Reversion only becomes a problem on engines with long duration cams at higher rpm when engine vacumn is low. As you are running a stock carb, I'm assuming (?) that your engine is fairly stock. You can run as tall an air filter as you like, I've run tall and short on a mildly done 1600 with no noticable difference. There is a great u-tube video of a Renault F! engine test. Talk about REVERSION........

brad

[mark tucker]