Upgrading '69 C10 to haul a car

[Spedy7]

So I'm a bit lost on this, I've been searching everywhere but can't find a solid answer. I want to upgrade my C10 to haul my '66 Mustang via open trailer (u-haul trailer) - what all should I be looking at? As its set up now, it was originally a 6 cylinder truck, but someone swapped in a 350/TH350. There's a small trans cooler, coil springs at the rear, bumper hitch (need a frame mount hitch for sure). Currently have no idea on rear end gears - my guess being somewhere around 3.50 or higher and I think a 12 bolt rear. Has drums all around and power brakes.

In total I'm guessing around 5000lbs for car+trailer (on the safe side - might also be throwing in some other stuff) - as it sits, would 3/4 ton springs swap right in? What all would you recommend I change out/upgrade?

[bonnieclyde100]

mine is basically the same thing accept my trans is a 700 r4. my diff has 3.73 gears and I towed a cargo trailer 3 times from Alabama to texas and the trailer had a weight between 5500 and 6000lbs total and mine did fine. now on my trailer I have a weight distributing hitch which helps a lot because coil springs are not the best for towing heavy trailers.

[bonnieclyde100]

oh I did upgrade the front brakes to disk tho.

[Coley]

Well you've already overcome a big hurdle (for free)...the rear end gears. If originally it was a 6 cylinder truck...then it came stock with the 3.73:1 rear end gearset...which is what you want.
So now you've got the 350/350 combo....hmm, not too bad.
Ok, so lets take a look at the other needed stuff:
-Heavy Duty radiator....nothing less than a 3 row/core radiator.
(hopefully it is not running the stock 6 cylinder radiator)
-Transmission condition....good? or?...make sure the trans cooler is a heavy duty type...don't go light duty here.
-Brakes...good condition? new?
-Tires...good condition? load range C (6 ply) minimum
As for heavier springs...what about adding the overload spring option for the trailing arm rear suspension?
I'm not sure what the tow capacity is but some of the guys have been able to produce some great GM charts from that era showing tow capability relative to motor and gear size.

All Good
Coley

[bonnieclyde100]

I agree with coley on the radiator had trouble keeping mine cool on first trip but changed radiator and it did better.

[Spedy7]

Originally Posted by Coley

Well you've already overcome a big hurdle (for free)...the rear end gears. If originally it was a 6 cylinder truck...then it came stock with the 3.73:1 rear end gearset...which is what you want.
So now you've got the 350/350 combo....hmm, not too bad.
Ok, so lets take a look at the other needed stuff:
-Heavy Duty radiator....nothing less than a 3 row/core radiator.
(hopefully it is not running the stock 6 cylinder radiator)
-Transmission condition....good? or?...make sure the trans cooler is a heavy duty type...don't go light duty here.
-Brakes...good condition? new?
-Tires...good condition? load range C (6 ply) minimum
As for heavier springs...what about adding the overload spring option for the trailing arm rear suspension?
I'm not sure what the tow capacity is but some of the guys have been able to produce some great GM charts from that era showing tow capability relative to motor and gear size.

All Good
Coley

Still have the 6 cylinder radiator I think - dinky little thing thst looks like it should be in a car. Can't say how good the trans is, but it's probably due for a rebuild. The trans cooler is a small one, I want to say 3×5. Brakes need to be replaced (sticking with drums since I plan on saving for discs on my Mustang). Don't know about the tires, previous owner let the truck sit for a few months and the tires got dry rotted so I swapped them for new cheap set of basic SUV tires. Would the overload suspension be fine? I don't want a super rough ride when empty but I also don't want to drag the trailer. Don't know if it'll change anything, but it's a long bed too. Motor is iffy - it's a 010 Mexico block and mismatched heads with terrible flow. Looking for a set of Vortec heads at some point or a decent cheap pair of repro/aftermarket heads. Should've been a 6 cylinder model though, door panel says CS instead of CE - someone replaced the glovebox so I don't have the paper there.

Still learning about these trucks - I'm a Ford guy (I share the love though). Loving the style of this generation of trucks though.

[Rich69shortfleet]

The half leaf overload springs are very effective. I haul an 18-ft trailer with a Chevelle on it and it travels very nice. Be sure the trailer you use has electric trailer brakes, help out a LOT. With a brake controller set up right you can have the trailer brakes do a lot of the work which really helps stop and keep control at all times.

The other nice thing about the overload springs is that you can remove them for regular driving or light duty so it won't "ride like a truck" so much. One bolt on each spring and they come right out.

Another important factor is to get the car centered on the trailer well. You want the bulk of the car's weight on the trailer springs, not on the hitch. Also, NEVER put the car on the trailer backwards with the engine end of the car on the rear of the trailer. You want the bulk of the over all trailer/car weight to be over or slightly in front of the trailer axles. Learn how to strap the car down well, never strap to the body or frame, always to axles or suspension components. If the location you are strapping to can bob up and down with the car's body, the straps can become loose allowing the car to move around. Strapping to the wheels is good if you have the right kind of straps. Also, one set of straps, front or rear, should be crossed (left side of the car strapped to the right side of the trailer and vice versa for the other side) so you have it strapped down properly for side to side motion. On a Mustang the rear is easy, that solid rear axle is a great strapping point. In the front you can either go around the wheels or the lower control arms. Strap the car, drive a few miles and check the straps again. Get them as taught as guitar strings.

[100%Chevy]

If you have doubts about the 350 trans-Don't rebuild it,replace it with a 700-R4! Especially if your rear is 373! You'll need the overdrive on the highway.
I have a 68,C-10 and pull a 18' car trailer with it.Mine is a 305,t-400 and 373 posi.My tires are P-235x15x75 and are too soft.I have the 2x2 frame hitch and air shocks.
I have an equalizer hitch but don't use it around town.No trailer brake controller even though the trailer has brakes.I need to fix that!
As said,you want to be very careful how you load your car on the trailer!You need more tongue weight for control,but not so much that you overload the rear of the truck to the point you lose steering control.And,to help prevent fishtailing!
Mike.

[joeydurango]

I know there are people that disagree, but I'd really think about converting to disc up front if I were hauling a 5000-lb trailer with a pre-71 C10.

[wbc409]

If you do put the 700r4 in your truck, it is recommended that you do not pull heavy trailers with the transmission in overdrive. It can generate to much heat and burn it up.
A class 3 hitch at a minimum, and a weight distributing hitch helps a lot.
Electric trailer breaks
Good radiator, transmission cooler.
Good tires, check the brakes.

It is easy to go faster than your brakes can safely stop you, drive like everyone else is an idiot.
I pull a couple of old cars regularly with my 71 c10 without any problems. I use an 18ft tandem axle open trailer with brakes on both axles.

[Rich69shortfleet]

Originally Posted by joeydurango

I know there are people that disagree, but I'd really think about converting to disc up front if I were hauling a 5000-lb trailer with a pre-71 C10.

I hauled a car on my trailer while my truck had drum brakes, ONCE. After that I immediately moved forward with the disc brake upgrade I had planned for the future. MUCH better. Drum brakes are not adequate if you have to do a lot of repeated stopping as fade sets in quickly when they are worked hard.

Drum brakes are one issue but at least manageable (unless fade sets in) but I'd never haul a heavy load like a car without trailer brakes, ever. At one time the brakes failed on the trailer (broken wire) and it was a huge difference to stop, wouldn't want to haul like that on a regular basis.

[Spedy7]

As planned, this is only a one-time deal. I'm stationed out in Cali and live in Arizona and I'm a pain in the butt when it comes to my Mustang (sentimental father-son value, prefer to keep it with me rather than have another company ship it). I've got about a year before I move back to Arizona and I'd prefer to just tow the car (that's what trucks are for after all right?). I'm fine with stiffer coils in the rear for that, or is it also possible to convert to leafs and at what price? I'm gonna order a 3-row radiator, new drums/brake bits front and rear, hitch (probably weight distributing), trans cooler, new rear coils (and probably front too to even it out, can't decide on whether I want HD C20 or standard C20 springs), and might look into a brake controller if it's not too expensive.

I know for sure I'll be going slow, probably a 12 hour trip or more. The uhaul trailers aren't the greatest - they all set the car the furthest forward on the hitch and strap the wheels there (don't want to buy a trailer ether). I need to flush the trans (smells burnt? I'm guessing because the cooler lines are near the headers) and put new gear oil in the rear too. It's a running project truck that's mostly there (killer deal at $1400), I'm guessing the previous owner's plan was to hot rod it (as guessed by the headers to glasspacks that dump under the cab).

[truckster]

Originally Posted by joeydurango

I know there are people that disagree, but I'd really think about converting to disc up front if I were hauling a 5000-lb trailer with a pre-71 C10.

You don't mention where you're going to haul the Mustang, but if it's anywhere with a significant amount of hills, I'd strongly recommend the disc brakes. I live in mountain country, and I hauled a car with my 70 C20 once - coming down a hill I couldn't stop for a red light. I was fortunate that I wasn't in an accident.

[MalibuSSwagon]

Advantage with uhaul trailer is they come equipped with hydraulic surge brakes, so that will help. Other advantage you have is the long bed, longer wheelbase is better for towing. You should be ok I've towed more with my 86 C10 short bed.

[truckster]

Originally Posted by MalibuSSwagon

Advantage with uhaul trailer is they come equipped with hydraulic surge brakes, so that will help. Other advantage you have is the long bed, longer wheelbase is better for towing. You should be ok I've towed more with my 86 C10 short bed.

You're right about the surge brakes (if they're adjusted correctly), but I just need to point out that your 86 has front disc brakes. The front brakes do the majority of the stopping, and discs don't fade the way drums do. Surge brakes only work when the tow vehicle brakes slow the trailer down. No braking on the tow vehicle means no braking on the trailer, either.

If it's relatively flat ground, I wouldn't worry about it too much. Just leave yourself room in traffic to stop.

[MARKDTN]

Originally Posted by joeydurango

I know there are people that disagree, but I'd really think about converting to disc up front if I were hauling a 5000-lb trailer with a pre-71 C10.

X3. Drums will stop eventually, but discs do it so much better. If I did only 1 swap on an old vehicle it would be disc brakes. Before p/s, a/c, radio, bigger engine.......

[Spedy7]

There's a couple mountain passes on the way heading from San Diego to Tucson (pretty long and steep, otherwise it's flat). Is it possible to do a junkyard front disc swap? Will a stock 3 or 4 row work fine as well for cooling?

[Coley]

A new or freshly steamed cleaned 4 row/core is the minimum radiator that I would use for what you have planned.
Remember....if you are stopped at the side of the road with an overheated truck (...and wife or girlfriend) waiting for a service vehicle...that extra $100, (or even $200 for the extra row) for the radiator will seem like a drop in the bucket.
If you intend to haul or pull with a truck, don't putz around...and don't compromise...get it right, get it safe....and it will be easy peasy, clear, comfortable sailing...because there is nothing worse than watching that temperature gauge rising past the centre point and to the right and no gas station, hotel with coffee shop and radiator repair center within 300 ft....noting that this kind of event usually happens in a relatively remote location.

My two bits.
All Good
Coley

[Rich69shortfleet]

Originally Posted by Spedy7

There's a couple mountain passes on the way heading from San Diego to Tucson (pretty long and steep, otherwise it's flat). Is it possible to do a junkyard front disc swap? Will a stock 3 or 4 row work fine as well for cooling?

I installed 71 disc brakes on my 69, all junkyard parts. Worked out great. Sending you a PM about a radiator.

[67 chevelle]

surge brakes on the trailer are a great idea , helper bags inside the rear coils will help if you have sag , and good tires