Thoughts on modified '72 GMC Sierra 1500 towing capacity? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

*Ozona* · 07-13-2009, 11:58 AM

Hi:

I've changed my Sierra 1500 around a bit, curious what the original tow capability is to safely tow and what (if any) my mods have done to that?

The truck was originally a 350/350, it's now a 509" 540hp/600tq BBC, Stage III 700r4, and has a fully welded Dana 60 and an upgraded driveshaft.

The truck is rear leaf springs, and is a long bed. I have a hidden hitch behind the license plate from ECE.

Thoughts/Comments/Opinions?

BossHogg69 · 07-13-2009, 12:12 PM

Good God, with 600lb-ft and a 3.06:1 first gear in that 700r4, you could put anything behind that truck that you wanted to! The only limit would be tearing the hitch off the frame! What's the hitch rated for? seems to me that'd be the only limiting factor as far as safety goes.

*Ozona* · 07-13-2009, 12:18 PM

It doesn't really have a rating posted that I see, I'll call ECE.

It's this one:

Class IV.

mrein3 · 07-13-2009, 12:38 PM

You're fine for pulling. The thing most people don't think about is stopping. If you're pulling a heavy load, you have to consider brakes. Especially if you don't rig up trailer brakes.

My stock configuration 1/2 ton pulls AND STOPS my bass boat just fine. It is about 3000 pounds with boat, motor, trailer and a full tank of gas.

I had to pull my convertible on a car trailer once. It was in the 5000 pound range. I was able to stop but I wasn't totally comfortable doing it and wouldn't even consider doing that on a long trip and/or on a busy road.

A lot of guys don't consider the stopping thing but realize that you are responsible for what you do out there. If you overload a trailer, can't stop, and take out a family in some little POS econo-box, you got problems.

LOW DOUGH · 07-13-2009, 01:01 PM

yeah, i think you can pull what you want. You just got to stop it.

EDIT: I would love to have that hitch set-up you got there.

*Ozona* · 07-13-2009, 01:02 PM

Quote:

Originally Posted by mrein3

You're fine for pulling. The thing most people don't think about is stopping. If you're pulling a heavy load, you have to consider brakes. Especially if you don't rig up trailer brakes.

My stock configuration 1/2 ton pulls AND STOPS my bass boat just fine. It is about 3000 pounds with boat, motor, trailer and a full tank of gas.

I had to pull my convertible on a car trailer once. It was in the 5000 pound range. I was able to stop but I wasn't totally comfortable doing it and wouldn't even consider doing that on a long trip and/or on a busy road.

A lot of guys don't consider the stopping thing but realize that you are responsible for what you do out there. If you overload a trailer, can't stop, and take out a family in some little POS econo-box, you got problems.

Good points.

I have ECE's drum brake upgrade in the back, think they're 3/4 ton drums. I have stock discs with slotted rotors up front and I've converted the truck from vacuum assist to hydroboost brakes.

dccarpenter · 07-13-2009, 01:10 PM

Assuming you have trailer brakes installed you can pull and stop most anything with that setup, I'd be perfectly comfortable pulling another truck or car on a trailer w/ brakes in your rig or pulling a dump trailer with a total weight of 7K or so.

Without trailer brakes I'd probably be comfortable with a car on a tow dolly at the most..though I've seen guys pulling half ton pickups behind an S10 using just a dolly, and despite all the naysaying and common wisdom to the contrary were pulling , braking, and stopping in downtown city traffic just fine.

69GMCLonghorn · 07-13-2009, 01:24 PM

I see idiots around town with old trucks like these that must have 1000 tons in the bed and another 4000 tons behind 'em... I saw a guy in a half ton on the bump stops a few weeks ago... Wait, he didn't make it... broke a U-joint... Never mind...

You sound like you already know your rig is set up to pull anything you want. As LHM has said, "Just jump in it and drive it!"... or tow it in this case!

Oh, and BTW, you know we need PICTURES of whatever you end up towing, right??

Arizona oldguy · 07-13-2009, 02:19 PM

Your engine and transmission sound like mules, however the rest of the truck is still a 1/2 ton brakes are important but remember you still have a 1/2 ton frame and such. When you are towing simply ask yourself one question can I stop this thing in time to stop from hitting that kid on the bike that just ran out in front of you. Hope your truck is everything you want it to be.

**john** · 07-13-2009, 03:22 PM

Tire ratings, suspension ratings drive train and brake ratings,is what the factory bases load ratings on. I would imagine your load rating are still what it says on your vin plate.

Longhorn Man · 07-13-2009, 03:31 PM

load it till it sways, then unload a few hundred pounds.
As long as you aren't one of the retards that working longhorn described, you should be ok

*Ozona* · 07-13-2009, 11:40 PM

Yea, asking you guys questions to help avoid the 'tard part.

Thanks for all the comments on things to watch out for, etc.

**special-K** · 07-14-2009, 07:02 AM

What exactly do you have for suspension.You have a leaf rear Dana60,right?Is the truck lowered?If so,how?If you have lighter lowering leafs you could rig up auxilary air bags.

*Ozona* · 07-14-2009, 08:02 AM

Quote:

Originally Posted by special-K

What exactly do you have for suspension.You have a leaf rear Dana60,right?Is the truck lowered?If so,how?If you have lighter lowering leafs you could rig up auxilary air bags.

I have a leaf spring truck, and I have a fully welded Dana 60 with a Torsen differential in it and 35 spline axels. The truck is stock ride height and has the correct springs for the big block up front and stock leaf's out back.

monte0185 · 07-14-2009, 09:50 AM

Sounds like your setup to pull just about anything you want. If you have stock half ton springs you may want to put a set of helper bags on the rear to help with toung weight but other than that a good setup for trailer brakes and your on your way sounds like. I have a 05 suburban that i haul a 16ft dove tail all over the place with cars trucks 4 wheelers you name it and have never had a problem.

**StingRay** · 07-14-2009, 12:15 PM

Trailer brakes required and watch out with that Torsen. If the trailer ever pushed you a locked diff will lose traction and the rig will jack knife. Open diffs,gov locks and elockers are really better for towing. I've towed 9K with my 72 LWB 350/TH350 with no problems on the prairies. It might not be so sweet in the mountains though.

*Ozona* · 07-16-2009, 02:51 PM

I'm looking at pulling 9500lbs or so, the trailer has disc brakes on it and 3 axels - looks like time to look at a much beefier truck?

Thanks again for all the comments, very helpful.

OlySezHey · 08-25-2010, 11:57 PM

Didja get it figured out yet? I'm starting to look into this too. Have you considered a weight ditributing hitch? If I remember right, I think the truck will handle 600 lbs tounge weight, and I guess that means with a wt dist hitch you can jack that up tp 900 lbs w/ a gross weight of 9000 lbs.
Have you seen this video? http://video.google.com/videoplay?do...0080037375587# "Weight Distribution Trailer Hitches Information"
Hope this helps

07-13-2009, 11:58 AM	#1
Ozona Account Suspended Join Date: Jan 2006 Location: Fort Worth Posts: 155	Thoughts on modified '72 GMC Sierra 1500 towing capacity? Hi: I've changed my Sierra 1500 around a bit, curious what the original tow capability is to safely tow and what (if any) my mods have done to that? The truck was originally a 350/350, it's now a 509" 540hp/600tq BBC, Stage III 700r4, and has a fully welded Dana 60 and an upgraded driveshaft. The truck is rear leaf springs, and is a long bed. I have a hidden hitch behind the license plate from ECE. Thoughts/Comments/Opinions?

07-13-2009, 12:12 PM	#2
BossHogg69 motor exploder Join Date: Mar 2009 Location: Pittsburgh, PA Posts: 2,346	Re: Thoughts on modified '72 GMC Sierra 1500 towing capacity? Good God, with 600lb-ft and a 3.06:1 first gear in that 700r4, you could put anything behind that truck that you wanted to! The only limit would be tearing the hitch off the frame! What's the hitch rated for? seems to me that'd be the only limiting factor as far as safety goes. __________________ Adam 1969 Chevy CST/10 stepside, DART Big M/TREMEC Magnum Extreme/3.73's w/Detroit Truetrac 1965 Chevy Bel Air Wagon (daily driver), 327/TH350,10 bolt w/3.08's 1961 Chevy Bel Air Sport Coupe, ZZ454/M21/9" rear w/3.50's & Detroit Truetrac 2005 GMC 1500 ccsb 2wd, 6.0L/4L65e/3.73 G80 2006 GMC 2500HD ccsb 4x4, DMax LBZ/Allison 6spd/4.56's w/Detroit TrueTrac Use the SEARCH function on this forum - it is your friend!! Last edited by BossHogg69; 07-13-2009 at 12:16 PM.

07-13-2009, 12:18 PM	#3
Ozona Account Suspended Join Date: Jan 2006 Location: Fort Worth Posts: 155	Re: Thoughts on modified '72 GMC Sierra 1500 towing capacity? It doesn't really have a rating posted that I see, I'll call ECE. It's this one: Class IV.

07-13-2009, 12:38 PM	#4
mrein3 Registered User Join Date: Feb 2000 Location: Center City, MN, USA Posts: 3,254	Re: Thoughts on modified '72 GMC Sierra 1500 towing capacity? You're fine for pulling. The thing most people don't think about is stopping. If you're pulling a heavy load, you have to consider brakes. Especially if you don't rig up trailer brakes. My stock configuration 1/2 ton pulls AND STOPS my bass boat just fine. It is about 3000 pounds with boat, motor, trailer and a full tank of gas. I had to pull my convertible on a car trailer once. It was in the 5000 pound range. I was able to stop but I wasn't totally comfortable doing it and wouldn't even consider doing that on a long trip and/or on a busy road. A lot of guys don't consider the stopping thing but realize that you are responsible for what you do out there. If you overload a trailer, can't stop, and take out a family in some little POS econo-box, you got problems. __________________ '70 cab, '71 chassis, 383, TH350, NP205. '71 Malibu convertible '72 Malibu hard top Center City, MN

07-13-2009, 01:01 PM	#5
LOW DOUGH I'M TRUCK CRAZY! Join Date: Oct 2006 Location: Sachse, TEXAS Posts: 1,737	Re: Thoughts on modified '72 GMC Sierra 1500 towing capacity? yeah, i think you can pull what you want. You just got to stop it. EDIT: I would love to have that hitch set-up you got there. Last edited by LOW DOUGH; 07-13-2009 at 01:01 PM.

07-13-2009, 01:10 PM	#7
dccarpenter Registered User Join Date: Jun 2009 Location: Washington, dC Posts: 176	Re: Thoughts on modified '72 GMC Sierra 1500 towing capacity? Assuming you have trailer brakes installed you can pull and stop most anything with that setup, I'd be perfectly comfortable pulling another truck or car on a trailer w/ brakes in your rig or pulling a dump trailer with a total weight of 7K or so. Without trailer brakes I'd probably be comfortable with a car on a tow dolly at the most..though I've seen guys pulling half ton pickups behind an S10 using just a dolly, and despite all the naysaying and common wisdom to the contrary were pulling , braking, and stopping in downtown city traffic just fine.

07-13-2009, 01:24 PM	#8
69GMCLonghorn Registered User Join Date: Dec 2006 Location: Porter Ranch, CA Posts: 978	Re: Thoughts on modified '72 GMC Sierra 1500 towing capacity? I see idiots around town with old trucks like these that must have 1000 tons in the bed and another 4000 tons behind 'em... I saw a guy in a half ton on the bump stops a few weeks ago... Wait, he didn't make it... broke a U-joint... Never mind... You sound like you already know your rig is set up to pull anything you want. As LHM has said, "Just jump in it and drive it!"... or tow it in this case! Oh, and BTW, you know we need PICTURES of whatever you end up towing, right?? Last edited by 69GMCLonghorn; 07-13-2009 at 01:24 PM.

07-13-2009, 02:19 PM	#9
Arizona oldguy Registered User Join Date: Jan 2009 Location: Queen Creek Arizona Posts: 56	Re: Thoughts on modified '72 GMC Sierra 1500 towing capacity? Your engine and transmission sound like mules, however the rest of the truck is still a 1/2 ton brakes are important but remember you still have a 1/2 ton frame and such. When you are towing simply ask yourself one question can I stop this thing in time to stop from hitting that kid on the bike that just ran out in front of you. Hope your truck is everything you want it to be.

07-13-2009, 03:22 PM	#10
john member #16 Join Date: Dec 1999 Location: Yuba City Ca. Posts: 3,618	Re: Thoughts on modified '72 GMC Sierra 1500 towing capacity? Tire ratings, suspension ratings drive train and brake ratings,is what the factory bases load ratings on. I would imagine your load rating are still what it says on your vin plate. __________________ john http://67-72chevytrucks.com/vboard/showgroups.php board vendors http://www.flickr.com/photos/1745471...7602865984234/ Last edited by john; 07-13-2009 at 03:25 PM.

07-13-2009, 03:31 PM	#11
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	Re: Thoughts on modified '72 GMC Sierra 1500 towing capacity? load it till it sways, then unload a few hundred pounds. As long as you aren't one of the retards that working longhorn described, you should be ok

07-13-2009, 11:40 PM	#12
Ozona Account Suspended Join Date: Jan 2006 Location: Fort Worth Posts: 155	Re: Thoughts on modified '72 GMC Sierra 1500 towing capacity? Yea, asking you guys questions to help avoid the 'tard part. Thanks for all the comments on things to watch out for, etc.

07-14-2009, 07:02 AM	#13
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,851	Re: Thoughts on modified '72 GMC Sierra 1500 towing capacity? What exactly do you have for suspension.You have a leaf rear Dana60,right?Is the truck lowered?If so,how?If you have lighter lowering leafs you could rig up auxilary air bags. __________________ "BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~

07-14-2009, 09:50 AM	#15
monte0185 Registered User Join Date: Oct 2008 Location: Brighton, TN Posts: 1,267	Re: Thoughts on modified '72 GMC Sierra 1500 towing capacity? Sounds like your setup to pull just about anything you want. If you have stock half ton springs you may want to put a set of helper bags on the rear to help with toung weight but other than that a good setup for trailer brakes and your on your way sounds like. I have a 05 suburban that i haul a 16ft dove tail all over the place with cars trucks 4 wheelers you name it and have never had a problem. __________________ A computer once beat me at chess, but it was no match for me at kick boxing. Duct tape is like the force. It has a light side, a dark side, and it holds the world together.

07-14-2009, 12:15 PM	#16
StingRay Senior Member Join Date: Mar 2000 Location: Saskatoon,SK,Canada Posts: 2,476	Re: Thoughts on modified '72 GMC Sierra 1500 towing capacity? Trailer brakes required and watch out with that Torsen. If the trailer ever pushed you a locked diff will lose traction and the rig will jack knife. Open diffs,gov locks and elockers are really better for towing. I've towed 9K with my 72 LWB 350/TH350 with no problems on the prairies. It might not be so sweet in the mountains though. __________________ Saskatoon, Saskatchewan Canada

07-16-2009, 02:51 PM	#17
Ozona Account Suspended Join Date: Jan 2006 Location: Fort Worth Posts: 155	Re: Thoughts on modified '72 GMC Sierra 1500 towing capacity? I'm looking at pulling 9500lbs or so, the trailer has disc brakes on it and 3 axels - looks like time to look at a much beefier truck? Thanks again for all the comments, very helpful. Last edited by Ozona; 07-16-2009 at 02:51 PM.



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08-25-2010, 11:57 PM	#18
OlySezHey Registered User Join Date: May 2010 Location: Des Moines, IA Posts: 46	Re: Thoughts on modified '72 GMC Sierra 1500 towing capacity? Didja get it figured out yet? I'm starting to look into this too. Have you considered a weight ditributing hitch? If I remember right, I think the truck will handle 600 lbs tounge weight, and I guess that means with a wt dist hitch you can jack that up tp 900 lbs w/ a gross weight of 9000 lbs. Have you seen this video? http://video.google.com/videoplay?do...0080037375587# "Weight Distribution Trailer Hitches Information" Hope this helps

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