Smog port plugs

[pose_442]

I'm needing the size and thread for the AIR injection holes. I'm needing some plugs, and don't have an old fitting to check with.

The engine is an 87 Olds 307 HO motor from a 442.

Thanks.

 

[85t5mcss]

Not 100% sure since mine r tucked away somewhere, but IIRC they were 1/4 tube thread nuts. Or thats what was closest to fitting.

 

[pose_442]

Cool, it's something to start with. Did they require a 9/16" wrench?

 

[85t5mcss]

Oh my, IDK. Prob 1/2" if I had to guess. Or u could always weld them shut. But reversing it becomes difficult that way.

 

[pose_442]

FYI: Smog tube block offs for exhaust manifolds

I have found the correct thread for these plugs. You need bolts or set screws (1/2"-20 thread).

If you use hex head bolts, you'll need 3/4" length. This is almost spot on with the shank of the tube nut.