How do I know what smog equipment my truck came with?

[R.O.B.]

Hello all, newbie here.  I recently aquired a truck from my uncle, and I wish to rebuild it, but here is the problem:

I have a 1983 GMC Sierra Classic, 4x4, long bed, 3/4 ton, over 8600 GVW, that orginally came with the 6.2L Diesel.  That motor cracked the heads, and my uncle pulled it before handing it over to me.  I have laying around, a good chevy 350 that I could put in it.  I checked with my state laws reguarding diesel to gas conversion, and they informed me that what ever the gas version came with stock, that's what I must have as well.  I do know that since I have over 8600 GVW, It should have less equipment.

I know I don't need cat converters, nor do I need the evap can.  I do know I need PCV valve, and an EGR valve.  But what else might I need? Smog pump? If so, how should it be hooked up? Anything else???

Please help, this is a nice truck, totally worth saving.

[Lt.Del]

I don't know why you say you don't need cats unless your state has some laws about older vehicles on the books. In Va, my 79 wont see the road unless the annual inspector sees a cat under her. If your state has those older vehicle laws, you dont need your other smog and emissions stuff either if you dont need cats.

As to what it came with, perhaps a reader here with a '83  can take a digital pic of the gray decal that is usually located on the radiator support that shows smog equipment and the routing of vacuum lines. Or, get a chiltons manual or haynes which usually display the different schematics of vacuum lines and what they go to. 

[Russ130]

I don't know why you say you don't need cats unless your state has some laws about older vehicles on the books. In Va, my 79 wont see the road unless the annual inspector sees a cat under her. If your state has those older vehicle laws, you dont need your other smog and emissions stuff either if you dont need cats.

As to what it came with, perhaps a reader here with a '83  can take a digital pic of the gray decal that is usually located on the radiator support that shows smog equipment and the routing of vacuum lines. Or, get a chiltons manual or haynes which usually display the different schematics of vacuum lines and what they go to. 

It doesn't need cats cuz its a 3/4 ton truck and it never had cats or a canister from the factory. 1/2 tons have smog equipment because they are basically cars on a truck frame. When you get up to 3/4 ton and up all the smog equipment is lost as well as the estimated mpg on the sticker. Of course now a days 3/4 tons and up have smog equipment.

r.o.b. - the only thing you should need is the egr valve. There is no air pump on an 83 3/4 ton to my knowledge.

[choptop]

My 86 1 ton has the smog and had cats that I have to put back on before I can get it inspected. I was told that they are normally less picky on cats on trucks pre 84 because that was the timezone between cats on all and no cats.

[VileZambonie]

What state do you live in? Why do you even need to inform anyone of the diesel to gas conversion?

[R.O.B.]

What state do you live in? Why do you even need to inform anyone of the diesel to gas conversion?

I live in Phoenix Arizona.  And I informed everyone about my conversion, so to point out my need for asking a question in the first place, and to hopefully avoid being asked dumb questions.

Thanks to everyone for helping out.  Does anyone have an 83 3/4 - 1 ton that can shed some more light on the subject?

Thanks,
Rob

[VileZambonie]

What state do you live in? Why do you even need to inform anyone of the diesel to gas conversion?

And I informed everyone about my conversion, so to point out my need for asking a question in the first place, and to hopefully avoid being asked dumb questions.

    

[Russ130]

My 86 1 ton has the smog and had cats that I have to put back on before I can get it inspected. I was told that they are normally less picky on cats on trucks pre 84 because that was the timezone between cats on all and no cats.

That is odd, I just sold a 88 3/4 ton no smog or cats on it and a good sticker. I think there is a good chance your 1 ton is a California model if it has all that smog equipment and cats.

R.O.B.- think about this, if your truck was originally a diesel there was no smog equipment or cats anyhow so why all the confusion to begin with?

[R.O.B.]

R.O.B.- think about this, if your truck was originally a diesel there was no smog equipment or cats anyhow so why all the confusion to begin with?

According to the guy I spoke with at Arizona Dept of something (I can't remember right now), he stated that reguardless of what the diesel cam with or without, since I'm converting to gasoline, I must have whatever equipment a gasoline truck came with.

[choptop]

Russ130, it very well could have beena California package, but I know for a fact its been in Texas all its life. It may have been ordered this way because the builder wated to be able to sell it in Cali. My 81 3/4 ton had the air pump, but no cats ( I have known the original owner all my life) and I bought a 79 3/4 ton that had the smog. All were bought in Texas, sounds unusual but may be a coincidence.
 R.O.B. dont you guys have emissions testing there. My wife has family in Phoenix, and I thought they had to have emissions testing on their trucks. It may be easier to go back with the deisel. I would rather have the deisel anyway, unless your looking for a hotrod.

[VileZambonie]

So once again, if your truck came through Diesel and emissions exempt why tell them you are converting it to gas? just leave it reg'd as a diesel.

[R.O.B.]

So once again, if your truck came through Diesel and emissions exempt why tell them you are converting it to gas? just leave it reg'd as a diesel.

My truck is NOT exempt! Metro Phoenix emission laws state 1967 and newer must go through emissions, with the exception of vehicles 5 years old and newer.  And to pass emissions, it must pass both the sniffer test and the visual test.  When I install the gas motor into my truck, providing all it hooked up correctly, DMV will convert thier computers to register my VIN as a gas vehicle instead of diesel.  Therefore, whatever was factory for a 1983 3/4 ton over 8600 GVW, my truck must have the same equipment.

[VileZambonie]

Can you register it as a collectible? That would make you exempt.

[choptop]

I like to visit Phoenix, but the emmisions crud is the reason I could never live there. You could probably tune an engine good enough to pass emissions without the smog junk, but they wouls still want to see the junk on there.

[VileZambonie]

If you have to just look compliant and pass the tailpipe test just run the egr and a cat. Run a thermostatic air cleaner and if you pass the tailpipe test they have nothing to bust you on unless they also test the Evap system.