David Vizard. How To Modify Ford SOHC Engines.
Std Carb airflow - 227cfm at 25" H2O (page 68)
Air filter case [NB US Pinto airfilter case] (page 64)
With case and filter - 199cfm
With case and no filter - 200.5cfm
With case & filter 1/4 taller (1/4gap between case & lid) 220cfm
Airfilters efficiency (page 63 & 64)
Motorcraft paper 99.2%
Fram 99.2%
AC 97.2%
Airfliters efficency on 350cfm Holley
8" case foam 92.2%
9" K&N no measurable loss
Standard manifold - 93% efficient (page 67)
Cheers
James