[Ant]

We did an actual dyno test on my KC alloy 373, using a universal spinners 1.5 dropped base and K&N E-3728R 2 ply un-oiled air filter 14" x 3.5", this air filter setup has approx 1-1/8" gap for the air to flow around the nice base which works real well, because, we did a side by side dyno run with no air filter and it made NO difference. My carb is a Pro-systems and right through our testing the operator who does a lot of F5000 Injected engines commented on the manners of my engine, we also found that a 1/2" carb spacer gave us 10bhp at the top end. Keith Craft did a real good job.

What the carb spacer does is allow the air flow to turn by giving more room after it leaves the carb, before it hits the manifold floor. Also I think a well designed filter base is important as it gives an area for the air to transition over, and as mentioned these smaller type air cleaners used on the FE 427 engines are only a compromise because of lack of room, but I guess work okay for road use!