Hello from Colorado. We own a 1984 w150,318 with a four speed. I am in search of a feed back carburetor. I read that Federal Emissions and High Altitude vehicles were equipped with an electric bowl vent. Could a Carter BBD be the right choice?
I also did a continuity check on the 02 sensor circuit. I found the circuit has been cut about six inches back from the Electronic Fuel Control plug in. The puzzler is that there is no cut wire coming out of the plug nor a empty slot/opening for the wire! I am desperate need of a wiring diagram/advice to get this vehicle to pass emissions. Thanks for reading..John

I have the Haynes Manual Emissions diagrams, and there is three pages on it, would that help?

*Edit*

It says:

Carter BBD
Carter Thermoquad
Holley 6145
Holley 6280
and Rochester Quadrajet

Yes that would help! Thank you very much!!

Okay, here you go:

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You'll have to rotate them because of how the book had to be placed on my scanner. I saved them right side up, but looks like it still defaulted to original image. That's weird, never had that happen before.

Curious how you will make out, let me know how it goes.

Thanks Grizzly!This will be a big help!

I am surprised that you need to have an Emission test on your '84 in CO. I live in WA and we use a rolling 25 year basis. My '87 D100 will never need another test even though I am sure it will pass a "sniff test" though not a "visual inspection"