Are these supposed to work on a stock manifold? There are two slightly different versions, both show up as EGR block off plate, but the one I got doesn't fit, don't know if I should order the other part # (9126BO). I like because they're stainless steel. The listings on different vendors are totally useless.

 

According to Summit, that part # is for the A.I.R. check valve block off plate. 9125BO is the part you need. Both are titled EGR Block Off Plate, but the notes gives specifics.

 

Thanks, but 9125BO is the one I already got (from Summit on ebay), it doesn't work due to the holes being slightly too small for the bolts, so they're lying X2.

 

Drill them out a bit...big deal.

 

Drilling through 1/8" stainless steel requires better tools than I have, and there's about 1/16" margin at the ends anyway so not enough, but thanks anyway for your very helpful comment.

 

Go buy a drill bit ffs.

So what if the edge is thin? It can be open ended and still have the bolts hold it firmly in place.....Anyone with creativity and some skill would find my suggestion helpful.

Drill it, use a washer, done.

I guess you couldn't use these headers cause the bolt holes are open, right?

 

I'm a little late but I hope this helps someone in the future.

I ran into the same problem with my EGR/AIR plates (I don't know what exactly I deleted) (2001 Camaro z/28)
Not only were the bolt holes too small, they were also too spread apart.

I used a death wheel/flat disc grinder to slot the ends. I eyeballed the rough outline of what needed to be removed, used a Sharpie to mark it, then ground out the material and checked to see if it'd bolt up to the manifold.

BE CAREFUL NOT TO GRIND IN TOO FAR OR THE CENTER HOLE YOU ARE TRYING TO BLOCK OFF WILL BE OPEN.

Also, you will need new hardware. Due to the difference between the flange thickness and the block off plate, the stock 25mm bolts bottom out. M8x1.25, 20mm long work fine, 15mm will work too.

Tips:
As far as the rest of the system goes, the valve thingy (drivers side, back of valve cover) that all of the hoses go to, it just slides up off of the bracket. You can only access one nut that secures the bracket. At least, I didn't try to find and remove the other one.

The pump deal in the drivers side front corner of the engine bay is easily removed from the bottom (ya don't say!). Remove the corner splash shield and it is secured by four 10mm bolts.

There is, what I believe to be, a vacuum hose connected to the top of that supply valve thingy. I just left that unhooked. Not sure what it does/will do. If you know, please enlighten me. Not sure if I should cap it off or what.

UPDATES:
I capped off that vacuum line. Still no CEL, driven roughly 150 miles over 4 days.
I popped off one of the plates to get some pictures.
If you're worried about looks, I included some pictures with the flange bolts in and tight. You can't even tell the plates are butchered.
One last thing. If you're worried about leakage from grinding the plates, don't. One picture is of the side that was blocking the exhaust port. You can see the carbon circle from where the exhaust was hitting it.

Hope this helps!