Square bodies, OBS rigs, bumpsides, dentsides, bullnoses and bricknoses. Everything you need to buy one right, keep it running, and find the dudes who get it.
Round fenders, simple wiring and the first 350 small block. Cheap to buy and easy to learn on.
“60–66”
The first of the coil-spring C10s and the last of the genuinely simple trucks. Six-cylinder rigs are still common and cheap to keep alive.
Watch for: Rockers, cab corners, and the rear window gasket on small-window cabs.
“Slick”
Wraparound windshield, clean slab sides, and the 300 straight-six — one of the toughest engines Ford ever built.
Watch for: Cab mounts and the cowl panel under the windshield base.
“67–72”
First year for the 350 small block, and the body that built the classic truck hobby. Best aftermarket support of any 1960s pickup.
Watch for: Front disc brakes only arrived in 1971 — on earlier trucks budget for the whole brake system.
“Bumpside”
Twin I-beam front end, optional 390 big block, and the last F-100s before the dentside. Short beds and Ranger XLT trim are the ones to find.
Watch for: Twin I-beam front-end wear and camber — an alignment shop will tell you quickly.
The square body lands, the dentside rules Ford lots, and diesel shows up for the first time.
“Dentside”
The F-150 nameplate was born in 1975. Roomier cab than the bumpside, better rust protection, and a serious following today.
Watch for: Drip rails, bed wheel arches, and the rear frame kick-up over the axle.
“Square Body”
GM's longest-running truck body and the most supported classic pickup on earth — sheet metal, glass, interior and wiring are all still being made new.
Watch for: Frame around the steering box, cab mounts, and rust in the bed floor and rockers.
“D/W series”
The odd man out, and that's the appeal. Cheap V8s, tough frames, and you'll be the only one at the show with one.
Watch for: Body panels are the hard part — inspect doors, fenders and the grille before anything mechanical.
Square bodies get square lights, Ford goes bullnose then bricknose, and Cummins changes everything.
“Bullnose”
Blunt grille with the blue oval front and center, and the 6.9L IDI diesel from 1983. Honest, overbuilt work trucks.
Watch for: IDI glow-plug systems and cooling-system maintenance — IDI diesels need the correct additive in the coolant.
“1st-gen Ram”
The 1989 truck was the first Cummins-powered pickup, and the 12-valve 5.9 is still the most-swapped diesel in the hobby.
Watch for: The killer dowel pin on 12-valve Cummins engines, plus cab corner and floor rust.
“Bricknose”
Aero-styled but still simple, fuel injection across the line, and the 7.3L IDI diesel arrived in 1988.
Watch for: EFI wiring and grounds, and E4OD automatic electronics on the later trucks.
“81–87”
Quad square headlights, better interiors, and 1987 brought throttle-body injection — the square body that feels modern.
Watch for: TBI throttle-body wear, and the 700R4 overdrive automatic's fluid and lockup behavior.
The OBS era: independent front ends, overdrive transmissions, and trucks that still feel like trucks.
“OBS / GMT400”
The truck everyone calls an OBS: independent front suspension, TBI then Vortec from 1996, and the 454 SS of 1990–93 as the collector piece.
Watch for: The 4L60E automatic, the 6.5 diesel's injection pump driver, and steering play from worn front-end parts.
“OBS Ford / Aeronose”
The last square-shouldered F-Series before the rounded 1997 body, and the 7.3L Power Stroke arrived in 1994.
Watch for: Twin I-beam front-end alignment and E4OD transmission electronics.
“2nd-gen Ram”
Cab-forward styling with the Cummins still in it: 12-valve through mid-1998, 24-valve after. A 2500 with a manual is the one to hunt for.
Watch for: Cracked dash and door panels, worn front suspension, and tired 47RE/48RE automatics.
“Square body” is the nickname for the 1973–1987 Chevrolet and GMC C/K pickups, and people use it loosely for the boxy GM trucks that carried the same body into the early 1990s on the R/V Blazer and Suburban. Round headlights and a slanted hood ran through 1980; quad square headlights came in 1981.
OBS stands for Old Body Style — the good-looking body that came before the rounded-off redesign. In GM talk it's the 1988–1998 C/K (the GMT400 platform). Ford guys use the same term for the 1992–1997 F-Series. It is not a trim level or an engine code.
Square bodies and GM OBS trucks, followed closely by Ford bumpsides and dentsides. Reproduction sheet metal, interior kits, wiring and glass are all in production. Dodge D/W series and 1st-gen Rams are the hardest to keep in body parts, so check panel availability before you commit.
Yes, with honest upgrades: an overdrive transmission, sorted brakes, new bushings and working air conditioning. Expect 12–18 mpg from a V8 and remember the crash safety is 1980s or 1990s at best. Treat it as a truck you drive, not a modern commuter.
Rust in bolt-on panels — fenders, doors, bedsides, tailgates — is a bodywork job with a known price. Rust in the frame, cab mounts, floor structure or the kick-up over the rear axle is structural, and it is where projects die. Soft frame spots are a walk-away.
Gas V8s are cheaper to buy, cheaper to fix and easier to find. The 12-valve Cummins, 7.3L Power Stroke and 7.3L IDI hold their value and tow far better, but a worn diesel is an expensive project with expensive parts. Buy the diesel for the work, not for the badge.
Square body and OBS questions, answered by dudes who own them.
Maintenance schedules, torque specs and repair guides.
Parts breakdowns, common failures and what the fix costs.
Discounts on gear, parts and tools for the build.
Shops, diesel specialists, dealers and towing near you.
Photos from the brotherhood, old iron included.
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