Now that my 85 with a 12A has a new exhaust ,where do all the hoses go that used to connect to the old exhaust? Including the flexible pipe that comes off the bottom of the air cleaner horn? I am not sure, but I think this might be the source of a vacuum leak?!! Since they are attached to nothing .

 

Pre-heat hose is removed, that's it. Did you remove and/or block off the acv? What about the other ports at the bottom of the air cleaner?

 

Every other hose under the air cleaner is connected. Other than the pre heater hose.

 

The flex hose is just a heater hose, having it on or off won't cause a vacuum leak, though you'll have to either disable the control for the valve that hose connects to or change the air intake completely, cause it'll cause restriction if it's stuck the wrong way.

The only hose that should be an issue for a vacuum leak (with just an exhaust swap) is the one going from the ACV to the cat, it's got a little metal bracket on the end of it that connects to the base of the carb manifold. Just block that off and you'll be good.

I'd also recommend the "rats nest" removal if you don't need to pass smog, it'll clean up the air cleaner hoses and make a lot of the possible vacuum leaks a non-issue.

 

The rats nest is something I am considering If can get up the guts to do it. I do not have to worry about emissions.ed