I've used the stock air filter on 289s, 302s, and 351s, and never had an issue with the engine running rich. The space over the carb is limited by the hood. The stock air cleaner has more room over the venturis than any open element type, and the stand off has never been a problem either. If it were, a spacer of any height can be put on top of the carb, and a correspondingly shorter one can go under the carb. I'll always recommend the OE cleaner, until I find something better. The expense of an OE air cleaner with all the parts shouldn't be much over 100. Put a post in "parts wanted". It's obvious the EB air cleaner looks different than others but it's equally obvious Ford put money and effort into designing and building it for a reason.