Ford broke new ground in 1980 by offering a revolutionary four-wheel drive front suspension and axle design underneath their newly designed line of trucks. They called the new front end design Twin Traction Beam (TTB) and it defined the Ford trucks so equipped right to the last year of its use in 1996
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In this three-part installment of Finesse 1-2-3, we’ll talk about the ’80-86 Ford "Bullnose" F-250 and F-350 trucks. They debuted for the ’80 model year as a complete refinement of the Ford truck line, and though their body style changed slightly in ’87, their technical aspects were foundational through 1996.
BACKGROUND: General Model Info
In this era, you had the option of Regular and Supercabs through most of the period, with the Regular Cabs on a 133 inch wheelbase and the Supercabs on 155 inches. Only eight-foot beds, or chassis cabs, were offered. There were also 168-inch F-350 Crew Cabs available from 1983. Some F-250 crew cabs are floating around from this era, but they appear to be special fleet orders. The trim packages varied somewhat during the era, starting off with the previous era’s Custom (base), Ranger, Ranger XLT and Ranger Lariat designations. These soon gave way to the Standard, XL and XLT Lariat models, which were usually available in all body styles, but not always with chassis cabs or crew cabs.
BACKGROUND: 1980-86 F-250 and F-250HD
There were two F-250 4x4s in this era, a light duty F-250 and the F-250HD. The differences were the GVWs (Gross Vehicle Weight), the HD being over 8,500 pounds and the “LD” (my designation, not theirs) commonly around 6,600 pounds, with some variations early in the era. The “plain” F-250 had a semi-float rear axle, lighter springs, a weaker chassis and different engine/transmission options. The F-250HD used the same chassis as the F-350 SRW and the same full-float rear axle, but was fitted with a lighter Dana 44 TTB axle up front. With suspension options, you could build an F-250HD to match the Single Rear Wheel (SRW) F-350.
In the F-250 line, the base engine was the 4.9L (300ci) six. The 5.0L (302ci) was the middle upgrade and the max engine was the 5.8L (351ci) V8. The ’80-82 F-250HD used the 5.8L as its base engine and had the 6.6L (400ci) as the top engine. With the intro of the 6.9L (421ci) V8 diesel for ’83, the HD engine options changed. The 5.8L remained the base engine but the 6.9L and the new truck version of the 7.5L (460ci) V8 gas were the high torque options.
Four-speed manuals (Warner T-18s or T-19s) provided the base tranny options while the burley C6 was the automatic option with all engines except the ’85 and ’86 F-250 with the EFI 5.0L, which had the 4-speed AOD automatic as an option. You can find some NP-435s mixed in there also, which were used in certain fleet orders or during shortfalls of the Warner gearboxes, The transfer case fitment was a little convoluted in the early days, with both the New Process 208 and the Borg Warner 1345 seen. By about ’83, according to Ford Data books, the Borg Warner 1345 had pretty much taken over.
Axles were convoluted in this era also. The light duty F- 250 used a semi-float Dana 60 or Dana 61 rear axle through ’84. The HD used a Dana 61 or Dana 70U full-float (depending on ratio) during the same period. In February of ’85, Ford introduced the big Sterling 10.5-inch ring gear axles in both semi-float (5,300 pound) and full-float (6,250 pound) forms. Up front, the F-250s used the Dana 44- IFS TTB, but, unlike the half-tons, leaf springs were employed.
BACKGROUND: 1980-86 F-350
The F-350 SRW and F-250HD were very similar trucks. In their standard forms the few differences were that the F-350 had higher rated rear springs and the heavier, 4,500 pound rated Dana 50-IFS Twin Traction Beam front axle. Early in ’85, the Dana 50 TTB was replaced by a Dana 60 solid axle in most applications. The F-350 4x4 dually is only listed as available after February 1985 and only as a chassis cab.
Except for fleet orders (where you could get a 300ci six), the base engine for the F-350 was the 5.8L V8. Through ’82, the 6.6L was the top engine. From ’83, you had the option of the 6.9L diesel or the 7.5L gas. Trannies and t-cases had the same options as the F-250 HD, either the Warner T-18 or T-19 or the C-6 automatic.
General Gas Engine Buildups
First off, bear in mind that the selection of buildup parts has narrowed for the older engines, especially the discontinued ones, such as the 400ci. In general, start with exhaust mods, headers, free flow single pipe systems or dual exhausts. Remember that really old cats have likely become restrictive with age, so a performance cat should be on the list as well, where applicable. From there, a free flow intake, air filter and a nice, hot ignition system upgrade are the most cost effective mods.
Most of the gas engines from this era are carbureted and some serious gains can be had by either replacing these carbs and manifolds with better pieces or going to fuel injection. Care must be taken not to go overlarge on the carb size or low end torque and driveability can be lost. A 5-600 cfm four-barrel will handle any of the V8s. An aluminum two-plane manifold offers the best performance for a ‘wheeling engine.
A throttle body EFI system is a cost-effective addition to a formerly carbureted engine, offering power, economy and drivability gains over the stock induction in leaps and bounds. If your Ford already has MPI injection, take care that all your proposed mods will work within the parameters of the injection system. If they don’t, high-flow injectors, rising rate fuel pressure regulators and new or reprogrammed control chips can be used to reconfigure the MPI for the new power output.
If you need serious grunt, without losing smooth low-end performance, one of the best ways to get it is via cubic inches. Don’t make a little dog do a big dog’s work. If that 5.0L is overmatched, swap in a 5.8L or a 460. The 4.9L six, 5.0L and 5.8L V8s all share a common bellhousing pattern. The 7.5L and 6.6L engines share the same pattern also and require a different bellhousing than the smallblocks. Swapping in a modern EFI unit can give you an engine that will run as smooth upside down as it does right-side up, plus deliver great power, torque and fuel economy. The 6.9L diesels use an IHC (SAE #2) bellhousing pattern on the engine side but has an adapter to the tranny, which is the so-called Ford “Diesel” pattern and is unique, though similar to the 460 style.
General Diesel Buildups
While the 6.9L will respond well to the typical exhaust and intake mods, remember this: There’s no excuse for a naturally aspirated diesel! Yeah, a Banks turbo kit is not cheap, but you’ll get more units of day-to-day usable power and torque per dollar spent than with anything else. A turbocharged 6.9L will exceed a first generation 7.3L Power Stroke for power and torque and isn’t all that far off from the later units. The 6.9L is an Indirect Injected (IDI) diesel with a high 21.5:1 compression ratio (’83-84 were 19.7:1), so without an intercooler, boost (and the appropriate fuel rate increase) should be kept relatively low at around 10psi, especially for a tow rig. The first turbo kits were non-wastegated, but the later ones are all wastegated types. The difference is low end performance. The wastegated turbos offer more boost at low rpms, which offer more spirited acceleration and less smoke. The non-wastegated types were better for long term towing because they offered less exhaust restriction and somewhat lower EGTs (Exhaust Gas Temperatures).
Specific Engine Buildups
4.9L Six- The one-barrel, carbureted version of the 300 six was the base engine for F-250 LDs, except in California where the 302 V8 was standard. It was not offered in the F- 250HD or the F-350, except in fleet orders. The early 1-bbl carb was known for being cranky, though the engine itself was brick-reliable. This old inline will do a pretty good small V8 imitation with headers, exhaust, a performance intake and a 2-bbl carb, or a TBI setup. If you are willing to sacrifice some low end, you could go with a 4-barrel and perhaps a mild cam upgrade. The guys at Clifford Performance are the Ford inline meisters and offer a great variety of hop-up stuff for the 300 six. The ’87-96 multiport injected 4.9L version was a sweet number that’s a possible swap. It made 145-150 hp and 265- 270 lbs-ft of torque.
5.0L V8- The Five-Oh is a Ford mainstay. A member of the smallblock Windsor family, the 5.0L was the standard engine in California and an option most everywhere else in the LD F-250. It has lots of power potential but may be a little short of cubic inches in some applications. Early 2-bbl versions (’80-84) will really wake up with a small 4-bbl or throttle body injection. The ’85-up EFI engines are potent and almost match the same era 5.8L four-barrel engines for power and torque. They are not all that “modable,” however, because they use an early EEC-IV speed-density EFI rather than the more flexible MAS (Mass Air Sensor) system. The usual intake/exhaust stuff works, but the stock EFI will limited the power potential. At that point higher flow injectors and rising rate fuel injectors can help, but these are really band-aids. Some people install aftermarket programmable electronics or adapt to a factory MAS system, the ’89-93 Mustang system being the favored setup. In general, take care with cam choices on the 5.0L so as not to lose low end performance.
1. The 2-barrel 302 is a bit light on heft for a working truck. An EFI 5.0L like this is better but still a little small for a big truck that mounts big tires and carries weight. There are lots of things you can do to both versions to increase the power, but displacement is the only answer when you need a big torque increase. The 302 is relatively uncommon in the F-250 lines.
2. The 351 Windsor, a.k.a. the 5.8L, is the minimum engine for a heavy working Ford in the ’80-86 era. The four-barrel HO is the best of that breed, but even the 2-bbl has a lot of potential. When properly modified, you can do most everything but heavy duty towing with this engine. The two barrels need a four-barrel and they all need headers and an exhaust. This really wakes them up. The next step would a mild “torquer” type cam.
3. The 6.9L IDI (Indirect Injected) diesel helped put Ford at the top of the pickup heap. While this naturally aspirated diesel doesn’t hold a candle to the modern stuff in stock form, if you just add a turbo kit, it can be a big surprise to all. DynoMax still offers a bigbore (4-inch!) exhaust system for the NA 6.9L engine and if you combine that with a freeflow air filter and turn up the pump a little, you can scratch at 190 horses.
FORD ENGINES: TYPICAL NET HP AND TORQUE SHOWN
CID/Cyls. Power@RPM Torque@RPM Bore & Stroke InductionYears
300/6 120@3400 229@1400 4.00x3.98 1-bbl ’80-86
302/V8 133@3400 223@2000 4.00x3.00 2-bbl ’80-84
302/V8 185@3800 270@2400 4.00x3.00 MPI ’85-86
351W/V8 136@3000 262@1600 4.00x3.50 2-bbl ’80-84
351HO/V8 210@4000 305@2800 4.00X3.50 4-bbl ’85-86
400M/V8 136@2800 310@1200 4.00x4.00 4-bbl ’80-82
6.9L/V8 170@3300 315@1400 4.00x4.18 Diesel ’83-86
7.5L/V8 225@4000 380@2600 4.36x3.85 4-bbl ’83-86
5.8L V8- The mainstay of many Ford buildups. If you have one of the early 2-bbl units (80-84), get a 5-600 cfm 4-bbl or a TBI injection kit. The ’85-86 HO (High Output) four-barrel engines are much more suited as a truck engine. Overall, the 5.8L engines have few vices or weak points and respond well to any and all massaging. They are big enough to be suitable for most levels of modification or use. They may be a bit small for the heavy end of the towing realm, even with mods.
6.6L V8- The 6.6L was a descendant of legendary 351 Cleveland. It had good breathing heads and a nice bore to stroke ratio. It needs only two things to come out of the closet for truck use, a good cam and timing gear and a four-barrel carb. The factory timing gears were retarded by the factory for emissions and an upgrade will really wake these engines up. The 400, and it’s cousin the 351-M (M for modified, really a destroked 400) all came with 2-bbl carbs, so you’ll have to turn to Edelbrock for a good two-plane intake and a carb. TBI works well also. With these two mods, plus a good free-flow exhaust, the 400 becomes a fire breather and more recognizable as a relative to the killer 351 Cleveland performance engine.
6.9 IDI NA Diesel- The air filters on these rigs need help, and combined with a performance 3 or 4-inch exhaust and a little fuel system tweaking, you can pick up some cost effective power (up to 8-10 percent). DynoMax builds a freeflow exhaust system. Still, the best bang for the buck is an aftermarket turbo kit from Banks or Hypermax. Though the numbers vary from each manufacturer, you can expect improvements in power from 30-50 percent and torque from 40-60 percent.
The ’80-82 400ci (6.6L) can be made to pull like a Clydesdale for relatively low dollars. Besides the usual exhaust mods, install a four-barrel manifold, like the Edelbrock, with a 600 cfm carb. Next, replace the timing chain and gears with one that isn’t retarded. Better yet, install a torquer type camshaft. You will then find out why the 400’s ancestor, the 351 Cleveland, had such a reputation.
Performance parts for the EFI in Ford earliest injected trucks are not common, but Jet’s early Ford module will help the 302 cope with big truck work.
Banks still produces the Sidewinder turbo for the 6.9L. It’s a wastegated unit that can offer up to about 250 flywheel hp and over 500 lbs-ft of torque. You might be fooled into thinking somebody did a Power Stroke swap!
7.5L V8- The 460 is the universally acknowledged Ford house-mover. It started out as a big car engine and became a truck engine. It’s direct ancestor was the 429, which is very similar. It’s immensely strong and as reliable as gravity. It became available in F-250HD and F-350 trucks from 1983 as the top-dog engine. It mounted a Holley 4-bbl that delivered a lot of trouble as well and single digit fuel economy, but all that is fixable with a carb change or an EFI swap. Don’t expect mileage better than the low teens at best from the stock engine. A good swap is the ’87-up EFI engine, even though it’s the less tunable speed density setup in the older trucks.
