Here's a pic view from what would be the rear of the truck.

That rusty tube you see just below the concrete block is the tube that runs from head to head on regular F series trucks. I guess your HD would be slightly different, with tubes or hoses runnung to the exhaust manifold(s) instead.

The two tubes at the bottom would run to your cats.

This is a side view from the drivers side.

The two tubes to the left would run to the air pump, I guess. I forget exactly how that went.

thanks LCAM, very helpful info. Can anyone take 1 picture of where the two air pipes connect after the cat? thanks

Holy cow what a clusterf*** this is, and here I thought the mess in passenger cars was bad! Then I guess it still beats the dual air pump setup some of the HD trucks got...


Actually it should be right before the cat, or directly in the side of the cat in the front part of it. Have no pic tho, I got a diesel and there ain't no cats on those.

thanks so much, i got it now

Yeah, that's the reason mine is now on the junk parts pile.

one more ? guys, I decided I am going to plug the two air holes in the cat for now and run it without the tubes. My question is: Do i need to plug the other end, meaning the two pipes that are not connected to the cat anymore or can those just stay open? thanks guys

Why not remove the air pipes entirely? But no, you don't have to plug the air pipes, just the cats/exhaust.

Personally, I'm of the opinion that if it doesn't perform a useful function, it can hit the *****can. Unless you need it for emissions compliance, or at least the appearance of emissions compliance. Just more parts to fail and need repair, more engine bay clutter, for minimal, if any, benefit. The air pump can be eliminated with a simple pulley and bracket (about $50 on Summit) and the whole mess can be tossed.

I know Conanski disagrees and seems to feel that you should leave all the original equiptment in place, whether functioning or not.

Just my opinion. You'll have to decide for yourself, I guess.

Rob

i just want to leave it all there in case i don't pass emissions, then i slap it back on. I live in Connecticut and we have lame emissions standards. The reason I am not hooking it up is cause I need two new air tubes and can't find them anywhere, even napa couldn't get them and I can't figure out on Rock Auto which ones I need