EGR to manifold thread size

[351 celi]

Does anyone know what the thread size and style is for the fitting which connects the EGR hardline to the oem exhaust manifold? It does not appear to be an NPT pipe thread like I assumed it was, and I need to block off the threaded port on the exhaust manifold. Thanks.

 

[81FairmontTX]

I know I'm responding to an ancient post, but someone might need the information that I've figured out.

I did an EGR delete on my 81 fairmont 200 six. the EGR tube that was attached to the exhaust manifold had fittings with an unusual thread size and pitch.

I determined that it is a 9/16-20 thread. That is a really difficult to find bolt. Some trailers use 9/16-20 lug nuts. Also the right hand thread of a bicycle foot pedal is 9/16-20. I went to a local bike shop and got 5 trash bike pedal take offs. I cut the pedal shaft off just above the wrench flats and screwed them in. They almost look like they belong there.