Swing Arm or Leaf Spring for towing?

[RUSSOM]

I'm interested in buying a 67-72 truck but I'm concerned about the swing arm/coil spring rear suspension versus the much rarer, for these years, leaf spring for towing. I'd rather have the 67-72, the 73+ trucks look to modern for me, but being able to tow this trailer is a must and I need the truck to have the ability to tow it safely. The trailer is an open type, total trailer & car weight is 7K. I'll be installing a gen 3 engine so I know I'm not limited on power, just very concerned about truck and rear suspension. Any thoughts?

TIA

[dwcsr]

Better upgrade the brakes. I towed a 6500 Lbs car and trailer and cooked the pads.

As long as you balance the load the coils will be ok. You can always use bags in the coils for added lift.

[RUSSOM]

I should've menitoned. Brakes & rear load bags, definitely.

But really what I'm after is I have know idea about the swing arm design and whether it is better or worse than the leaf design for towing. The only argument I've heard FOR the swing arm is that they were probably more expensive than the traditional leaf setup and that is the only reason GM went away from the swing arm. I'm really having a tough time with that one though considering all current 3/4 & 1 ton truck rear suspensions are leaf, but I wanted to confirm or hear a strong argument one way or another here before I jumped into this deal. As crazy as this may sound I've listed my 04 Duramax for sale, I don't drive it everyday anymore, and I want something smaller but still able to pull my trailer, and I like the styling of the 67-72 trucks.

Thanks guys

[Jacfourteen]

Welcome to the board. If you're concerned about the strenth there are plenty of aftermarket companies that sell tubular control arms that are stronger than the stock 40 year old ones. you can also get reinforcement brackets from lmc or use a 3/4 version that is a little beefier. I would suggest swaping the coils for 2600 lb air bags that way you can adjust for load. Good luck!

[Jim_PA]

I know where you can get an auxiliary leaf setup for the coil spring trucks (G60 option code...). It's another route to consider You'd get the ride and handling of the coils, and the added trailering/hauling capacity of leafs.

I don't know how much extra weight the auxiliary leafs are good for, but they look pretty beefy.

[jbristo67]

You would be fine with the rear coil suspension. I pull a 6500 lb boat with mine

[argonaut]

There's nothing wrong with rear coils. In fact, putting my engineer hat on for a minute, I'd argue that it is structurally stronger: the trailing arms take the pushing/pulling loads and the coil springs + dampers can focus on purely vertical loads. I think the only drawback is that the panhard bar doesn't keep the rear axle centered as the suspension travels through its range of motion. However the panhard bar is better for cornering because it transfers the load from the axle directly to the frame, without trying to twist the leaves that are also supporting the vertical load. The leaf suspension is also cheaper, and provides less unsprung weight, but I think that both these points are moot on a towing vehicle.

Either way, you'll be fine. A good brakes, good springs + dampers, and good bushings and you should be all set.

[68gmsee]

I have towed a Massey Ferguson 135 with a 6 foot Bush Hog with my 350/350 chevy 69 with no problems. I think total weight would be about the 6500-7000. I have the stock trailing arm suspension and shocks and drums all around. You just have to watch the stops because of the weight involved.

If you intend to beef it up a little, you shouldn't have any problems.

[Ackattack]

I too think that either would be fine for towing, however a positive for the leaf springs is that there is a natural anti-roll characteristic with them since you have to twist the leafs to get body roll. The coil springs don't have this "feature". You can always add an anti-sway bar though. Also, this assumes the bushings on the leaf springs are good.

[Longhorn Man]

the main thing you need to do is make sure the bushings on the trailing arm rear are all good. If you plan to tow that much all the time, then you need to look into a 3/4 ton (coils were still standard on the chevy) Again, if doing this kind of work all the time, I would recomend poly bushings.
Both coil and leaf were rated for the same payloads and towing rate, so that is not a real issue, it's the handeling aspect of them that is what we are talking about.

[Dingfodgy]

As Longhorn Man said: both suspension setups will work fine as long as they are in good mechanical condition. If you go with 1/2 ton- then adding helper bags or overloads would be a good idea. The brakes are a limiting factor in these trucks. An upgrade in this dept. is crucial. Also, I don't know if you have brakes on the trailer, but if you don't I would look into installing either electric or hydraulic surge brakes to assist in stopping.

[70rs/ss]

I pulled two sets of 3/4 ton trailing arms off of longbeds at the wrecking yards as they are plated up and way beefier than the 1/2 ton arms. You can purchase a 1/2 ton and add the bracing to the trailing arms and add the 3/4 ton coils and have the 1/2 ton truck w/3/4 ton towing capabilities. I'd definately put new springs, and trailing arm bushings and urethane for sure. Add a rear sway bar and you are ready to haul. A diesel would be a nice upgrade to the 67-72 a 6.2 or 6.5 drops right in!

[RUSSOM]

Originally Posted by Longhorn Man

Both coil and leaf were rated for the same payloads and towing rate, so that is not a real issue.

Do you remember what that number is? Just curious.

[RUSSOM]

Great info.!

Every post has been exactly what I’ve been looking for and I appreciate you guys taking the time to reply. Sounds like I'm going to be at the upper limit, weight wise, of what some of you have mentioned you’ve pulled before, I just hope the rig is safe like this at highway speeds, 70-75 mph. There’s trailering to the track safely, and then there’s just dragging it there with white knuckles. I don’t want to be the latter.

Reading through the responses and noticing the other vehicles in y'alls signatures you guys look to have some fun toys! I also noticed that ackattack had a 99 FRC, that’s actually what I use my truck to pull...it’s just the trailer itself that is extremely heavy.

I'm looking for a 67-72 2WD shortstep and I’ve put together the following list of parts to ensure the truck is as safe as possible:
LQ4/4L80E
New suspension bushings
4 wheel discs
Load bags in the rear
Coil springs, Adj. Panhard, Shk. Mount Locators, Bilsteins
Moog front end rebuild kit: inner & outer rod ends & adj sleeves, U&L ball joints and control arm shafts, idler & pitman arms
HD rear trailing arms with bushings
F&R sway bars

Looks like these companies have pretty comparable prices and similar selections:
Early Classic
Classic Parts
Classic Performance, seems to really concentrate on suspension & brakes

Am I missing anything in that list? Do those suppliers have a good following and quality parts? Any others I should look into or parts to consider?

Thanks again guys!

[Longhorn Man]

I eould get a long wheel base personally. I've towed with both, and the longer trucks just do a better job.

[fine69]

Originally Posted by Longhorn Man

I eould get a long wheel base personally. I've towed with both, and the longer trucks just do a better job.

I 2nd this motion. If you are pulling anything longer than a 12 foot utility trailer with a SWB the truck feels "squirrly".

Been there, done that.

[argonaut]

I agree. While short bed trucks are sweet, especially when going to the track there is no end to junk you want to bring with you, and a long/fleetside bed will give you more space to put it all.

[RUSSOM]

Here's what I've found on wheelbase length:

1967
The 6 1/2 foot short box C10 wheelbase was 115 inches
The 8' C10 & C20 was 127 inches
The C30 9' was 133 inch wheelbase.

Chevrolet introduced another model in 1970, the C20 Longhorn. It was built on the 133 inch wheelbase and featured an 8 1/2 foot box

So to sum it up, if this info. is accurate, you gain 1' of WB between SWB & LWB, C10/20 and another 6" between C10/20 LWB and 1 ton and heavier duty suspension as the tonage increases.

Just for comparisons sake here is some info. on the 1995 model C/K trucks
SWB 117.5
SC/LB 131.5
EC/SB 141.5
EC/LB 155.5

After reading the replies and doing some more looking around I also found another thread on something similar from Jan of this year a few minutes ago, I will go out on a limb to say this, and I guess let the flaming begin, but drivers of the 3/4 and 1 ton trucks seem to be better prepared to tow their load than the 1/2 ton guys. It seems that most 1/2 ton guys aren't using trailer brakes, really don't have their trucks prepared to haul b/c that probably wasn't their primary reason for purchasing, but the ones that are, seem to be doing ok. Obviously weight distribution and tongue weight are the name of the game, but if hauling a car, thats as easy as finding the sweet spot on the trailer, marking a ref. point and then always repeat, make changes on placement based on payload weight.

Obviously I'm trying to keep myself talked into a SWB for pulling my race car, but...

[ETsC10]

I personally would aim at a '71-72 3/4 Ton GMC.
If you like the looks of a Chevy, change the nose.
And, I agree, a long bed tows far better.

[RUSSOM]

I found this too.

Per a 1977 issue of N.A.D.A Used Car Guide:-

1972 Ship Weight

C10 - Pickup Stepside 6/12' ............3560
" " FleetSide 6 1/2' ........................3630
" " Stepside 8' ..............................3640
" " Fleetside 8' ............................. 3720
C20 - " " Stepside 8' ......................3940
" " Fleetside 8' ..............................4030
" " Longhorn 8 1/2' .........................3950

The ship weight
is defined as the shipping weight less fuel, coolant and lubricants.
weights per gallon ( lbs per gallon) fuel - 6; oil - 7; water 8.

1968 GM Restoration Guide Curb Weight No Rear Bumper heaviest entry, each class...
C10 SWB 3640 lb CE10734
C10 LWB 3745 lb CE10934
C20 LWB 4133 lb CE20934
C20 Longhorn 4195 lb CE21034
C30 Longhorn 4357 lb CE31034

[SCOTI]

Originally Posted by RUSSOM

....I'm looking for a 67-72 2WD shortstep and I’ve put together the following list of parts to ensure the truck is as safe as possible:
LQ4/4L80E
New suspension bushings
4 wheel discs
Load bags in the rear
Coil springs, Adj. Panhard, Shk. Mount Locators, Bilsteins
Moog front end rebuild kit: inner & outer rod ends & adj sleeves, U&L ball joints and control arm shafts, idler & pitman arms
HD rear trailing arms with bushings
F&R sway bars

Looks like these companies have pretty comparable prices and similar selections:
Early Classic
Classic Parts
Classic Performance, seems to really concentrate on suspension & brakes

Am I missing anything in that list? Do those suppliers have a good following and quality parts?

Be sure & check out the reviews section of the board for manufacturer 'grading'. Look in the 'bad deals' section for sure.... http://67-72chevytrucks.com/vboard/f...splay.php?f=26 .

[70rs/ss]

Get a 3/4 ton or if you are destined to have a trailer back there a lot, look into the longhorn, but then you'll have leaves vs maybe coils in a 3/4 ton.

Avoid CPP as per the review board, customer service, not so much!

[ed2552]

Um, chevy's had the coils, GMC's had leaves. I think our 67 C20 would be great at hauling a lot. I know my grandpa's C2500 has towed a ton of crap over the years, and it's worked just fine. I would have no qualms about either a coil or leaf spring truck. I know our C20 has helper leaves that contact the trailing arms that act basically as overload springs. If you want to haul a car, and that's why you're getting the truck, i'd get a longbed. More room for stuff, and better towing manners, because there's more frame and wheelbase for stability.

[70rs/ss]

Well, technically they both had both, leaves more common on GMC's but they got coils and chevies got leaves. Some 3/4 ton and I believe all one ton C30's had leaves though.

[RUSSOM]

More looking around...

A friend of mine I go to the track with has a Yukon Denali, the short one, Tahoe length, that he pulls his enclosed with and a 98 trans am inside. Here are the specs:

2004 Tahoe
overall length (inches): 198.9
overall width (inches): 78.9
overall height (inches): 76.5
ground clearance (inches): 8.4
wheelbase (inches): 116
front track (inches): 65
rear track (inches): 66
curb to curb turning circle (feet): 38.3