Hey guys,

Disclaimer: I have had a 3.4L v6 since 2002. In October I bought an LT1 and started building it up. So I'm a virgin to the LT1s.

So when I bought EGR blockoff plates, it was for the back of the intake manifold and one for the exhaust manifold. What do I do with the vacuum lines that are on the intake manifold that are for EGR and AIR? Do I just thread a solid bolt in or leave the nipple open [thus introducing a vacuum leak?]?

Also, and I apologize for how newb these questions are - I bought the AIR blockoff bolts. Where do those go and are there any other secondary lines that must be closed up?

 

I ditched mine when I did headders. I did the block off plates like you mentioned. Plug the manifolds however you can, not sure if they make high temp thread sealant. Remove the air pump when you do it, that will get rid of that pump.

 

about the vaccume lines plug them with brass plugs. and on the headers for the air pump delete i used 2 1/2 inch pipe plugs and put them in as tight as i could. First time i did the plugs on the headers with nitrous i blew them out. havnt hit the button since.

 

There is a single connection on the driver's side of the intake manifold for the EGR. You put a "vacuum cap" (small rubber cap, available in any auto parts store) on the nipple. What year is the engine out of? There is no vacuum line for the AIR system, unless the engine is 95 or newer and had the AIR pump recall work done on it. In that case, they ran the AIR solenoid vacuum line to the same intake manifold vacuum nipple as the Opti vent vacuum line, and added a "tee" so both lines would be connected to the same point. In that case, you would remove the "tee" and connect only the Opti vacuum line to the nipple.

Never leave a vacuum nipple open.

The bolts go into the AIR connections on the exhaust manifold (or in the AIR connections on your headers, if they are "emissions" headers with the correct connetions). Again, the method for plugging the AIR connections depends on the year of the engine. 93 only has an AIR connection on the driver's side (passenger side is combined with the EGR connection). 94/95 manifolds and SOME headers need a 22mm oil drain plug. 96/97 need an 18mm plug. But some headers have male threads for the AIR connections, and need "caps", not a bolt.

These are the parts you would be removing (courtesy of Shoebox):

http://shbox.com/1/diverters.jpg

You can see where the tubing flare nut threads into the exhaust manifold on each side.

Your air intake ducting, from the filter to the MAF sensor will have a 5/8" connection on it for the air supply hose to the AIR pump. That connection also has to be capped with a 5/8" vacuum cap, or you will be pulling unfiltered air into the engine.

Again, depending on the year of the PCM, you may have to have the codes/SES light turned off when you remove the AIR and EGR. 96/97 OBD-II PCM's are the most critical in that respect.

 

Thanks for all the information! So it looks like I bought the AIR block offs when I didn't need to - bought LPP s.s. headers with ORY and I don't believe they have the openings for AIR. Also, thanks for the information on the nipple plug (sounds dirty LOL). I'll definitely have to look into that.

 

Thanks for making me laugh.

 

Hopefully the laugh was at the nipple plug comment and not at my stupidity for buying plugs for something I won't have with my headers.