I put a 4" tall K&N filter on the green 67 today and I had pretty good results.

The throttle off idle was a little bit more punchy, but at higher RPM's is when it really started to shine. I guess the old paper element was just too restrictive at higher speeds.
Anyone else have good luck with a K&N?

 

have you tied a sunstacker from K&N?
ive read about them and curious to see if anybody has tried it

 

I've used cotton type filters for years for high performance applications.
I think eZ meant stub stack, which I haven't tried.