1986 K30 7.4L TBI swap for CO emissions??

[1986K30]

First off, great site I must say.

I have a 1986 K30 with the 7.4L. It has all the smog equipment from the factory. I was entertaining the thought of doing the TBI swap. My only previous experience with the GM TBI was on my long gone 1987 V2500 Suburban. I really enjoyed the benefits of the TBI while 4 wheeling up at 10-12,000 feet here in Colorado. That is my main reason for wanting to do the swap in the first place. It would also be nice to not have to go through my starting ritual every morning...

I was hoping that someone may have some experience here with the in's & outs for this scenario in Colorado. More specifically, can I ditch the smog equipment and swap over the TBI stuff from a 87' or newer 454?

Any help will be appreciated!

Thanks

 

[RetroC10Sport]

Paging Jim...

 

[Jims86]

I dont know Co's smog laws regarding efi conversions(the bureaucrats call it engine change)
It depends on where you are in Colorado, and if you have smog inspections...In Ca for instance, Most of our border counties do not have smog checks, unless the vehicle is sold.
The best thing for you to do, would be to get in touch with the state governing body regarding emissions testing and certification to see what the rules are...aircarecolorado I think its called.
I DO know it has been done, and the general guidlines, and what I always suggest, is to get all OEM GM parts to do the swap, including Delco sensors. The best place to source the hard parts, would be here, or on Ebay, or a wrecked 454 truck at the wrecker.
You can also take a 350 or 305 throttle body and have it bored, and install the bigger injectors...Again, all at OEM specs for 87 to 92.
The small block throttle body bores are 1 11/16" each, and the BB 454 is 2".
You will also be reducing the amount of emissions equipment by swapping to TBI...you will have EGR, EVAP, Thermostatic air cleaner, and MAYBE the smog pump.
NO AFTERMARKET PARTS! At least untill it is certified, then whatever is game for the 87-95 is fair game for you. I dont even recommend TBI adaptor plates, because of the large void underneath, that has caused problems with slight bogging and crappy driveability. Try to find a 454 TBI Intake...they are out there.
And the best thing is...we will stick with you through the whole swap!

 

[1986K30]

Thanks for the help Jim!

I'll contact them directly and go from there. I was in a county that was emission free up until two years ago. First it was the bordering Denver metro counties now its the bordering, bordering counties... It's all some type of tier step process towards the CA type emissions. I must admit that it has me wondering if its worth the hassle? The one good thing is that I don't need cats since the truck never came with them in the first place.

 

[Jims86]

Thanks for the help Jim!

I'll contact them directly and go from there. I was in a county that was emission free up until two years ago. First it was the bordering Denver metro counties now its the bordering, bordering counties... It's all some type of tier step process towards the CA type emissions. I must admit that it has me wondering if its worth the hassle? The one good thing is that I don't need cats since the truck never came with them in the first place.

But if the 87 had a cat, you need it. I know some 3/4 tons had them.
Edit: Just looked at the walker site, and you will have to ask when you call the air people, But the Cali V30 had a single exhaust system, with a cat, andnthen another cat after the muffler. The Federal was a catless dual system, which may be what you have now.