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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: rick69 on October 03, 2017, 11:33:39 AM

Title: 85 GMC 305 V8 Exhaust Air Injection Tubing Nut Size 22mm X1.5
Post by: rick69 on October 03, 2017, 11:33:39 AM
I removed the air injection system from my 85 GMC 305 engine. I checked on the internet for the tubing nut thread size but could not find the info. My truck has the 2 large tubes that thread into the front of the exhaust manifold. I cut the pipes and then used a 22 mm deep socket to remove the nuts. I measured and suspected the nut thread was a 22 mm 1.5 thread so I ordered a 22mm by 1.5 nut from Fastenal. Sure enough, that is the correct thread size.  This has probably been posted before, but I could not locate this info on the net and hope it helps others in the same predictament!
I found Stainless steel drain plugs at BelMetric.com. DP22X1.5HSS product number.
Title: Re: 85 GMC 305 V8 Exhaust Air Injection Tubing Nut Size 22mm X1.5
Post by: DouglasBeale on October 26, 2018, 08:06:48 AM
Thanks Rick, I wish I found this post before. I had the same problem and spent more time searching the internet for the bolt and bolt size then I did taking them out and putting them in. I needed 8 - PAIR manifold plugs for my 86 K30 350 engine. I found them at NAPA - Part #: NOE 7041048 (they are oil drain plugs). They only went in about half way, and cost about $40, but turned right in no problem.
Title: Re: 85 GMC 305 V8 Exhaust Air Injection Tubing Nut Size 22mm X1.5
Post by: Ed4all10 on October 26, 2018, 07:07:02 PM
Sounds like you need a set of headers on your beast now!
Title: Re: 85 GMC 305 V8 Exhaust Air Injection Tubing Nut Size 22mm X1.5
Post by: DouglasBeale on October 27, 2018, 09:00:59 AM
Sounds like you need a set of headers on your beast now!

Yes sir... But it will probably have to wait till spring.