[wilf leek]

FWIW, I use the K&N # E-1963 filter on my oval air cleaner. (about 1 3/4" tall element). Engine is a 408 windsor stroker, revving to 6000, so I guess airflow requirements are substantially similar to yours.

No difference on dyno with/without the filter, also no significant manifold vacuum difference between the two at WOT. Thus I conclude that this air filter is not restrictive.

I have always wondered about those tiny H&S filters on the original cars. In theory they are way too small. Any comments from the cognoscenti?