Smog Help 81 with a 454
 

We just got a 1981 3/4 ton GMC with a 454 in it. It has no cats on it, or smog equipment and down here in Las Vegas, Nevada it is required to be smogged.

I have been looking for engine diagrams and info, and can't seem to find too much.

My questions are
what is all the stock smog equipment that goes on a 454?
and where can I find it?

Thanks for any and all help!

O and what would be the best cats to put on it for a good price?

Re: Smog Help 81 with a 454
 

If it was the heavier 3/4 it might not have had factory smog equipment, i know my 77 3/4 doesnt. I think they made some 350s nonsmog till like 82 or 84, but dont quote me.

Re: Smog Help 81 with a 454
 

The service manual should have a diagram in it showing the the hose routing anf wiring for all the sensors. Hopefully that will give you some tip offs. I'd ask the guys at a testing center maybe they could offer some help.

Re: Smog Help 81 with a 454
 

I don't have the service manual with it, and how do I tell if it is a heavier 3/4 ton? Thanks

Re: Smog Help 81 with a 454
 

In 1981 a heavy duty 3/4 ton,(C6HP package), would be in the "heavy duty emissions" category. This would include trucks of 8,500 gvw and above. If your truck was original with the BB it also would have a FF rear end. I don't recall them as being loaded with the emissions/catalytic converter package.

Re: Smog Help 81 with a 454
 

Hmm I am not sure, I will have to look into it more, thanks Dooley.

On another note, does anyone know the stock emission crap that goes on a 454? Egr valve,smog pump, smog pump bracket, what else? Thanks

Re: Smog Help 81 with a 454
 

If it's an HD Emission vehicle it will still have a smog pump with the AIR system. My duallies are both 454's with the HD emission system, they have smog pumps but no catalytic converters. It's listed in the owner's manual and the factory shop manual. If the truck is an automatic it will have an EGR valve(manual trans. doesn't have an EGR valve), smog pump, bracket, AIR system manifolds with injector pipes, and the rubber hoses that go from the pump to the injectors.

Re: Smog Help 81 with a 454
 

Check to see if the rural counties surrounding Clark county have emission checks.

For example if Nye county does not test just register the truck in Pahrump.

Re: Smog Help 81 with a 454
 

Thanks, how would I register in Pahrump if I can't show that I live there? We have some fam in Washington, and it already is registered up there, but is that illegal to do?