Hey Jed, I keep meaning to ask just *where* in Tenn ? I spent close to 12yrs in Memphis.
Well, there are actually a whole bunch of diffrences between the 78's & the 79's but most of them don't matter to guys outside of Bronco enthusiasts & by the way, those round-headlight Bronco's are fairly rare. Ford made a running change mid-year to the rectangular lights so most late year 78's have them. It's only the early to mid-year trucks that sport rounds.
In 78' the Broncos were considered HD vehicles (because they exceeded 6000GVW) and therefore exempt from emissions but in 79' the EPA upped the HD limit to 8500GVW so the Bronco came under emissions regulations as a Light Duty truck & that's where most of the diffrences lie. Incidently, this is why it's legal in Cali to swap the 460 into a 78' but not a 79' (sort of). The 78' was classified as a HD vehicle but the 79's weren't, 79's were Light Duty trucks and have to meet Light Duty emissions requirements (it's actually more complicated than that, like everything in Cali is, but that's the easiest explanation I could give without delving into engines that were smog certified without a chassis and such. There *are* loopholes that let you put one into a 79' but the documentation requirements are different, Arrgh, it's *already* giving me a headache. This is why I don't live there anymore). There's just no end to the wierdness. There are also a whole host of skid-plate diffrences between them depending on the size of the gas tank & things like that. You can go crazy trying to keep track of it, but here are the diffrences that I can remember off the top of my head:
78's could run leaded or unleaded with no restrictor in the fuel neck
78's had a regular fuel gage but 79's had the "unleaded fuel only" gage
78's have no emissions hole in the fuel tank & no coffee can but 79's do for the evaporative return hose
78's had no catalytic converter (excep CA) but 79's did
78's used a mechanical throttle linkage but 79's used a cable
78's used the smaller 1310 U-joint & yoke while 79's used the larger 1330
78's used the older power steering pump & pressure hose while the 79's used the "new" version
79's for some odd reason would NOT let you order both the CB radio AND the oil bath air cleaner, that one's wierd.
78's & 79's use different key-cylinder to door-latch rods. The design changed between years for some reason
79's were the only ones offered with the muffler skid-plate
79's were the only ones to come with chrome yellow wagon wheels (freewheeling package only)
78's have the CB behind the driver's seat, 79's have it behind the driver's cargo panel. Go figure.
78's had black handles for stuff like the wing windows & passenger seat latch while 79's were chrome (79 pass seat latches were bigger too)
There are also diffrences between the chrome moulding around the rear cap windows (locking strip vs. no locking strip), and some between the gages (black or silver piping & backgrounds & stuff like that) but then you're REALLY getting into the tiny diffrences between trucks. I figure that just knowing that only the early to mid-year 78' baseline trucks had the rounds is good enuf for most guys, but hey you never know when you'll need to win a bet at the bar. And keep in mind that none of this even *begins* to address some of the strange option combos available to our fine Canadian brothers to the North, plenty of those rigs have filtered down to us and complicated the issue.
