Which K&N Filter?
 

Looking to install a new K&N X-treme filter/assembly. I'm thinking 9 or 11 inches (diameter) but I'm not sure how tall I'll should go. 3 or 4 inches? I have a Superformance with a 393W / Vic Jr. intake combo. I'm not using a carg spacer plate. Any ideas?
Thanks.
Scott.

Late response...sorry...
 

Just swa your question....I, too, have an SPF w/ 393 stroker. You didn't mention what distributor you're running, but it indeed has a bearing on your air filter selection. I'm running an MSD6AL, with billet MSD distributor. The distributor cap is wider than the Ford Duraspark cap, and interferes with the K&N 14" drop base filter canister. If you're running the Duraspark ignition, you should be able to use the K&N 14" drop base unit along with their filter, no problems.

I'm running a 13" Ford Motorsports filter canister along with a K&N filter. Fits fine, good air flow. But, there's a clearance problem with most SPF cars so you may be limited on the filter height. I understand the K&N X-Stream filter system actually flows less air than the 13" Ford Motorsports filter set at the proper height. From what I undestand the pleated top actually causes some air turbulence and effectively reduces the air flow. The 'proper' height for the Ford M/S air cleaner is about 3" above the carb intake plenum, higher if you can get it. What you're tying to do is allow the air flow to straighten out after it makes the 90 degree bend and to do that, you need to increase the length of the intake plenum - by raising the top of the air cleaner.

We got all this info fro a dyno tuner in the Charlotte, NC, area. He's known as one of the best Ford tuners in that part of the country. He got about 13 more horses by recommending the K&N drop base unit, but like I said I had clearance problems with the MSD distributor.

I've got all the part numbers at the house if you'd like them. Everything's available from Summit Recing, if you're interested. Let me know...

Thanks for the info Freddie.
I just ordered (and received) from Summit a 9 inch K&N filter with a 9 inch X-treme top. It is not a drop base.
As for which distributor, I'm using a MSD billet (PN 8578 maybe?). It's the small base with a black cap and no vacuum advance. I'm also using a 6AL with a Blaster 2 coil.
I'll be having the car put on a dyno chasis in the next few weeks. We'll be adjusting the jetting and timing to look for that "magic" combination. I suppose we'll look at air cleaners as well to see what works. I'll let you know.
Scott