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1975 Bronco emissions (truck/ Car) question for a coyote swap

gws34

Jr. Member
Joined
Jan 29, 2005
Messages
128
I am looking for info that someone here most likely has the answer....

SO I am looking into doing a Coyote swap in my 1975 Bronco. Here in AZ in the city area's I still need to do emission testing every year. For the rules of swapping an engine here is that it is required to use the same GVWR as the vehicle it is going in. So that means I can use the Mustang or F150 engine. But the catch is that is has to have the same classification of emission systems that was in the original vehicle.

SO my question is, Is the 1975 Emission system in the bronco considered a truck system or a automobile system?
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
49,364
Good question. During the time our Broncos were still in production, that status changed almost every other year. So some years it was rated as a "passenger car", other years it was a "utility vehicle" (or truck) and maybe even had it's own category at some point. You could get a Bronco in CA with either Commercial plates or passenger car plates. Not sure if that was by year, or by category, or by the original intent of the first entity to register it. Broncos got the breakerless ignition systems and catalytic converters about the time passenger cars got them in '74, but before pickups did. Some categories of even F150's did not get the charcoal canister or electronic ignition until '77 and later.
I think that's why we could find an air pump on a '66 in CA, but not on a '69, then missing through '73 (at least in CA) and then back for '74-'76 and so on. Years mentioned just approximate.
Hopefully someone here knows how they were rated in '75.

But does that really make a difference there? Isn't the rating for the new engine donor? Are they still separated, or do they all meet the same standards now?
I thought (perhaps naively) that new vehicles all work under the same smog specifications until you get into the heavier trucks? Meaning isn't a Mustang engine going to be the same as the very light duty F150 engine as far as emissions? Or is it still a variation on each category?

Obviously I'm just spitballing here and joining the future conversations. Not fully up on my Coyote lore.
Do they care during your inspections (check carefully enough) to know that when you use an F150 engine for example, you have to use components from a Mustang just to get it to fit a Bronco. Are they checking specific numbers and looking for everything?
I remember when 904Bronco here did his first major EFI swap into a Bronco that needed inspections (the '77 I think?) and used a Mustang engine. When he went in to get it approved they wanted to see ALL the Mustang stuff, including full dual exhaust, four catalytic converters and O2 sensors, vacuum reservoirs that he didn't need, and probably a few other items.
Just wondering if they really check that stuff or not. I think most areas do not, but was curious.

good luck.

Paul
 

Viperwolf1

Contributor
electron whisperer
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Aug 23, 2007
Messages
24,346
It was considered under the 6,000 lb GVW and less category.
 

Attachments

  • 1975 Ford Light Trucks and Vans Emission Equipment.pdf
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ntsqd

heratic car camper
Joined
Jan 30, 2005
Messages
3,896
Loc.
Upper SoKA
For the KA commercial vs. passenger car plates I suspect that it was dependent on if it had a full hard top or not. Full length hard tops likely got passenger car plates and roadsters & 1/2 Cabs got commercial plates because they had an accessible bed.
 
OP
OP
G

gws34

Jr. Member
Joined
Jan 29, 2005
Messages
128
I am trying to find out what the differences are and what the inspectors would know and not. Do they really know what the difference is on the charcol container from a f150 to a mustang are. Overall it is a PITA. I just don't want to spend the money and time to do a swap and then have them fail it and it is not registerable here. I will go with the info as viperwolf said that it is a under 6000 lb. The way I translate that now is that the f150 motor is out since it has a gvw of 7000+. I will continue to research this. F150 motors tend to be a little cheaper (and have the low end torque) but maybe i should just stick with the mustang motor..

Yes the way that the az Emissions office described it to me is that EVERY single piece of emissions equipment from the donor vehicle needed to be transfered over. So yes all the cats, canisters, o2 stuff, all of it.

It was told to me that it will fail at first site as to being a modified vehicle every year and then I need to go to the second line for detailed inspection and if all is right it will pass. But every year I have to go through this process.

I want to do this the right way and legally but they sure do make it tough. No wonder every tries to find a shortcut and bypass the system.
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
49,364
Sounds like you’ve dug into a little bit and already talked to the people that will ultimately make the decision.
They can’t tell you that a bronco with 4500 to 4900 pounds GVWR from 1975 is approved to use the pick up engine right off the bat?
Or it’s ruled out completely on the other hand?
 

904Bronco

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Bronco Guru
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Sep 28, 2004
Messages
6,022
Loc.
San Martin, CA
I have documented my challenges here years ago on transplanting an 88 Mustang motor with a NV3550 manual trans into my former 77 Bronco.
I had the experience with the Fox body chassis and access to parts. I soon learned that I knew more than the Smog Ref here. And yes correct ECU for manual, all smog components installed and functional. Including 4 cats, dual exhaust, which I had to make myself as exhaust shops are not supposed to install used Cats. Had to get a letter from Aero fuel tanks that their tank was CA compliant. You can call the DMV or speak with other Smog Ref's on any given day and the story will change. It doesn't matter if the tail pipe is cleaner than with the factory motor, it is all about the visual. Which makes no sense to me.

So be sure to get the straight scoop before proceeding...

I put a late 80's GM TBI truck motor in my 77 Landcruiser. Smog Ref asked me if I had a check engine light? Yes. Well I am sure we will find something else to fail you on. He didn't. We went round and round with the Cat. 77 was a non Cat chassis, but the 80's motor had one. He had a little more respect for my work after checking my rig. Said you need a Cat, I said based on the materials on line if you make me install a Cat on a vehicle that didn't have one from the factory, then the State assumes the liability for fires. He called the State and waited on hold for 20 minutes. He hung up and made a command decision, no cat required. But he said when you get some miles on this fresh motor, you will not pass the tailpipe inspection. And the Old Guy was right... I had to put a Cat on it and fab up some shields that were found on later Landcruisers.

Good luck.
 
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