1977 J20- what OEM emission controls?

[Dave Jeeper]

There is a 1977 J20 401 manual tranny for sale locally. Did this vehicle come with air injection and a catalytic converter? The power steering pump has a 2 groove pulley but there is no second belt and there is no air pump.


We have emission testing where I am.

[tgreese]

The TSM for each year has a table that lists the devices installed depending on equipment and model. Yes, I expect it will have air injection (a smog pump).

Page 4A-41 https://oljeep.com/edge_77_tsm.html

The 401 with the T-18 was only offered in 1974. After that, automatic only. Something has been changed. A California 360 with the 4-speed would have a cat, 49 states not.

You should put your general location in your profile so that it appears with every post.

[Dave Jeeper]

Denver, Colorado Just added to profile.

[tgreese]

What tests do they have in Denver? In CA it would not pass (I presume) because the engine does not match the VIN. You could ask the seller for the VIN minus the last six digits. Look at section 1A of the TSM; sixth digit will be N, P, Z for 360 2V, 360 4V or 401 resp.

[Stuka]

Here in CA, I have never had an emissions place actually check the side of the block to see which AMC V8 it is. And the 401 and 360 look the same except for the block casting. So it being a 401 is most likely not an issue.

The air pump would be required, CO didn't require cats until '79 I think? But besides the air pump, you also need a correct carb, and all the vacuum stuff.

tgreese above put you on the right track to see what engine it would have had. If its a 360 4v, it can have a smog legal 4v carb. But if it was a 2v, then you need to swap on a 2v carb, which 401's did not come with.

[tgreese]

I presume the inspection station would know to look at the valve cover tag?

Also possible that it was a 401 with automatic converted to a manual. Seems less likely. That's another case where the VIN will not match what's present, if they care (transmission type is in the VIN).

[78basewag]

Here's a link to a picture from out of the Mitchell emission control application table manual. Hopefully the link works.


https://photos.app.goo.gl/k4TByQfPgP7QtMtE7

[Mtnmax]

I did not write the original post, but I'm pretty sure I looked at (and bought) the same 1977 J20 referred to in the Denver area. It turned-out to not be a 401, as advertised. It has a 360, which enabled me to knock down the purchase price considerably. All the emission equipment has been removed, but I live in a remote area of the Colorado mountains where we are not required to get an inspection/sniff, so that's not an issue for me.