Specs for Plenum Bolt (nipple in back)

[BaadVR4]

Since almost all the block off plates are the same thickness and the stock bolts for the pipe between the rear O2 sensor and the intake are the right length, just get two more bolts that match those. Lowe's, Ace hardware are both sure to have what you need.

[HLxDrummer]

Got the EGR bolts but the two 1/8" pipe plugs I got don't fit

[BaadVR4]

Plugs too small? Try next size larger pipe thread size, 1/4". Sounds like someone once upon a time stripped out one or more ports and then just decided to re-tap them. Since the original threads were NPT, it would make sense to use NPT for the re-thread. In any case, it is now a trial and error situation.

Last bit of advise: If possible, don't use straight threads. Pipe threads were made for a reason (they seal much better, especially in situations where the joint is subject to pressure differential in both directions) and they continue in use because they are the best solution to the problem. Depending on how large the existing holes are, you might be able to drill and re-tap to 1/4" NPT. If I had to, I would have the holes welded and start over at 1/8" NPT.

Got the EGR bolts but the two 1/8" pipe plugs I got don't fit

[HLxDrummer]

If anything it is too big. I can get it to go maybe one or two threads and that's it. Don't really wanna tap it. If anything ill just weld the nipple shut or something.