Ordered a 3" AF1 as I have no tuning. After installed noticed the OD seems more like 3.75 or 3.5, now I'm worried the wrong part was sent and my motor is running lean. Any other ways to tell?

 

There is an inner and outer tube. The outer tube should be 3.5, inner is 3". When they do the 3.5" tubes, they just leave out the inner tube. Pull off the filter and see what the ID is, but chances are you're ok.

 

The smaller 3" section is only 7" or 9" long and it's on the throttle body end where the mass air sensor goes. The air filter end is 3.5" on all sizes.

 

Apparently Ford changed the design some because my MAF actually mounted halfway on the actual intake. The instructions showed what your talking about though. So I have the 4-5" rubber reducer that goes from the intake to the throttle body, the MAF mounted halfway down the intake then the filter had it's own hoseclamp and just mounted to the opposite end of the intake

 

how did you install that 4 to 5in reducer. i got the 3.5 af1 for my 4.6 from troyer but i could not fiugure out how to install that reducer. am i maybe missing something.

 

The smaller portion goes on the throttle body with the smaller hose clamp to secure it ands the larger side goes over the intake with the larger hose clamp securing it. Make sure after you get everything adjusted you tighten those clamps as the intake moves when the motor moves