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I was wondering if anyone knows what the differences between 78 and 79 Broncos are? I am talking differences involving drivetrain and emissions. Any help is appreciated.
When I got my '79 inspected it failed miserably because it did not have cats. I told the guy doing the inspection this truck never had them and learned this- '78 Broncos did not have them, '79 Broncos did. So I got Street Rod plates (no inspection required).
I do not know about the A.I.R. system but mine is all gone and can't find a replacement...
Sorry, kind of went off on a tangent there...
BFW
both the 78 and 79 broncos had dana 44 front axles and ford 9" rear axles. the engines were eithe a 351m or a 400; the transmission was either a 4 speed manual or a c-6 automatic; the transfer case was a full time 203 new process or a new process 205 part time.
The '78 avoided all the emission stuff by coming in at 6100GVW--no cat, so no AIR system. The '79 does have the cat and the systems that go with it. I had a '78 Custom with a 351M and it was real basic. Back then, the GVW determined whether a truck had emission control. Heavy trucks avoided it for a while longer. I think that's why the '78 stayed around as long as it did.
My 79 has no cats. the sticker on the hood says NON-CATALYST.
I wonder if it can be found out if my truck had cats with the VIN number? I sure would like to have regular tags instead of Street Rod plates because I can only drive occasionally with those plates. Maybe I can find that non-catalyst sticker and put under the hood...
BFW
You could try the sticker, but the other visual would be the filler neck. My 78 has the large filler opening, a cat model would have the small one. Of course you could change that too
BFW, if your 79 was cat equipped, it would also have "unleaded fuel only" printed on the fuel gauge. I have heard that some very early 79's didn't have cats. They were probably left over 78 models retitled as 79's.
One other difference is the 79's were equipped with larger driveshaft
U-joints. The only cosmetic difference was round headlights on the base model 78's; the 78 XLT and all 79's had rectangle headlights.
My '79 has a large filler neck, the inspector accused me of having removed the restrictor plate in the neck. I wonder what he thought my motivation was since all U.S. gas station nozzles are standard now, why would I remove the restrictor plate?
I just checked and my fuel gage does not say "Unleaded fuel ony" rather it just says "FUEL". I could not find a sticker that says non-catalyst, but the truck has been repainted so it might be under some flat black. After all, I had to scrape off the gloss red to get to my VIN # decal. So where would I find the sticker?
So as far as I can tell, my truck might not have ever had cats and the inspector did not know his 70's Fords too well...
BFW
My 78's sticker is on the driver's side valve cover. Many of these are missing, as you can imagine on trucks this old. The sticker is available as an aftermarket item.
BFW, it sounds like either your's is a very early 79 model, or has been converted to "fool" the emissions inspectors. (There is also an "Unleaded Fuel Only" sticker behind the fuel filler door on the 79's, but it's easy to remove.)
You already have the larger filler neck, and the "correct" 78 fuel gauge. You could add the Non-Catalyst sticker, and see if they would pass it.......