can anybody tell me what this peice with the red and yellow covers on it is for and why did i get a smaller stovepipe with the MOD one with new APN/ UIM?
[/img]

That'* the vacuum fitting for the rear (firewall side) of the UIM. The large one goes to the brake vacuum booster. The reduced diameter stovepipe provides additional protection to the UIM by allowing a larger air gap. There are two to allow for variances between the years. I'd bet that Bill Buttermore will be along before long to provide more details on that.

As Archon mentioned.. if you look at the backside of your manifold, you'll see the port it goes into.

As mentioned, the two stovepipes are provided to allow for the variations between the 95-98 and 99+ LIMs. You use the correct one to fit yours.

Wow! This is great news. This is an APN kit, right? If so, that means that now both Dorman and APN are providing TWO stovepipes. It would seem that they actually listened to us (and probably lots of others) who requested that they include pipes for both the older and newer engines.

The stovepipe with the larger diameter base replaces the stock 3/4" stainless steel stovepipe in lower intake manifolds built from 1995 to 1998. The stovepipe with the smaller base replaces the stock 5/8" aluminum stovepipe in lower intake manifolds built from 1999 to 2005.

I would like to think that our talks with the development people at APN and Dorman had something to do with this. Now, if Dorman would get off the dime and install a sleeve in their UIM, all would be well. Until then, the APN is gonna be the preferred choice, hands down.

We continue to learn