We've taken on my in-law's 1976 F-250 to eventually become our travel trailer tow vehicle in a couple years, but being that old, it obviously doesn't have the same information about tow capacity etc that a modern truck would.

Spec that I've ascertained so far is:

1976
F-250
2WD Supercab
155" wheelbase
460 4V engine
C6 transmission
Dana D60, 3.54:1, limited slip diff, 5300lb rear axle
7100lb GVWR

It's badged as a Trailer Special.

After this, it starts to get into conjecture...

I can see from a brochure that a 1977 F250 4x2 looks to be trailer weight of 7500 max, or possibly 8000, with a class IV hitch (does a "load equalizing" hitch back in the day = WDH today?), but a '76 could have different ratings to a '77, I suppose - haven't found the Ford Recreation brochure for 1976 online yet. The '77 brochure does list the same axle ratio that ours has, with a minimum of a 400 V-8 - the 460 in ours would presumably just make it a slightly more accomplished tow vehicle, rather than able to increase the trailer weight etc - correct?

I haven't taken the truck to the nearest CAT scale yet to get actual weights, but it's also confusing that the '76 Ford Trucks brochure lists the SC as having an 8100 GVWR, but the warranty plate on the door and door frame stickler both say 7100..

Any ideas?

 

Take this truck back to when it was brand new, I'd feel comfortable pulling 10K via fifth wheel or goose neck and 8K with a WDH. Since it's 40 years old I would have to do my own complete bumper to bumper inspection and rebuild..., frame, suspension, brakes, tranny, engine, etc just to leave my own home county with it.

IMO, tow ratings for this vintage (if you can find them) are a maximum assuming everything is in excellent shape. Problem is manufacturers left it up to your own judgment because we didn't have the culture then like we do now of hitching up horrendous loads and hitting the interstate and 60+ mph.

 

Expecting a 40 year old truck to perform like it did when it was new just isn't realistic unless you bring the axles, brakes, suspension, drivetrain and frame back to new condition. Forty years of use and abuse on a truck takes its toll, and if you just tried to hook it up and tow, I bet you wouldn't make it 200 miles before something serious broke. If you want a reliable and capable tow rig, this is a much bigger project than you probably realize.

If it were my project, I would strip it to the frame and carefully inspect it for damage and cracking, especially around where the steering box mounts. Repair any rust and rust-proof the frame. I would trash the stock axles and swap in a pair of '05+ superduty axles. I don't really think 40 year old axles and brakes are worth messing with. Engineering and manufacturing have made enormous strides in the last 40 years and there are vast improvements in serviceability, reliability, and sheer strength.

You could keep the stock engine and transmission, but be aware that this combination isn't going to be kind to the gas budget. Expect 6 or 7 towing and maybe 10 empty.

I'd probably consider swapping in a newer engine/transmission combination. Maybe a V10/5R110? That would be nice but I think you'd need a lot of the interior and gauges for it to run right.

Now you know why you never see 70s pickups towing modern RVs. It just isn't feasible.

 

I would disagree on the above, as my old truck was a 77 F150 Supercab 2wd. I used it to pull things all over the west as did my grandfather. Its all about maintenance and inspection. Since these trucks are really old by most standard you will want to have the frame checked along with the suspension components if you are unsure of their condition.

My old 77 had 4.88 gears and would pull anything you put behind it. I kept up with any maintenance/repair it needed but you also have to be proactive.

I would totally be comfortable jumping in my old truck, hitching up my current TT and going for a 1K plus trip, but if I had any doubts on doing that I would fix the issue.

Everybody has a different opinion

How heavy of a trailer do you want to pull?

 

Hoping to keep it under 5000 - closer to 4000 if possible (two bunks and a fixed bed are the main criteria)

 

Ok with that little weight, you can discount a lot of what I said. I would still go through the axles, brakes and drivetrain very thoroughly before doing any towing though.

 

GVWR does not reference towing. only the truck and anything in the truck. "The gross vehicle weight rating (GVWR), or gross vehicle mass (GVM) is the maximum operating weight/mass of a vehicle as specified by the manufacturer including the vehicle's chassis, body, engine, engine fluids, fuel, accessories, driver, passengers and cargo but excluding that of any trailers."


GCVWR does. "Gross Combined Vehicle Weight Rating (GCVWR): The GCVWR is defined as the maximum weight of a loaded vehicle and its attached loaded trailer. And like the other weight ratings discussed here, the vehicle's manufacturer calculates this number"

 

Hmm, looks like the 1977 Ford Recreation brochure stated GCWR of 13000

 

No need to swap axles or drive trains. Just inspect frame and replace wear components like suspension bushings, axle seals, springs, shocks, complete brake job all the way around including hoses and master cylinder. Properly rebuilt 460 and C6 can handle a heck of a lot. You'll be plenty good for 5,000lbs of towing.

I'd expect 10mpg gallon empty and 7ish towing because it's 460 cubes and a C6.

Before you begin, be honest about the frame condition. If it's nasty rust then might want to move to plan B... i.e another truck.

 

You can tell some more if you pull a front wheel. There were single piston calipers trucks and dual piston with the latter being 8800GVWR (or there abouts). '76 F250's had both options.

 

so many forget suspension bushings... front and rear...
replace steering "RAG"... Please.

SPRINGS age.. replace them also.. and NEW "U" bolts...

 

Yep, definitely replace spring U bolts. Places like Detroit spring make the rear leaf springs according to factory specs.

2X on replacing the steering rag. And don't forget the king pins.

 

It's a long term project before we even get to buying a trailer, and included in the project is all the suspension/steering/brakes revamping.

 

Just been to the CAT scale, and with a topper on, but no-one inside, about 1/8-1/4 tank of gas in the main tank (auxiliary tank contents are unknown at this time), with a hitch:



So 7100-5240 = 1860 payload for people, gas, stuff, and the tongue weight, correct?

 

Yep, you got it right. 7100 is the most you're rated to weigh. In other words, your GVWR = 7100lbs.

That's the short easy answer. IMO as well as many others, the long answer is it's more important to not exceed your axle ratings. Many new truck buyers today weigh their empty truck and then look at the door tag on their new F150, F250, or F350. The result is often a surprisingly low payload capacity if you only consider the gross vehicle weight rating (GVWR). Strict adherence to many new truck GVWR's drastically reduces their tow ratings due to trailer hitch weight. For this reason, many folks will verify their final axle weights are within their axle ratings even though they are technically over their GVWR.

I wouldn't sweat it too much if you weighed say 7500 lbs fully loaded and hitched so long as you didn't exceed either axle rating.