Track width question - '56 3100 on '61 chassis - The 1947 - Present Chevrolet & GMC Truck Message Board Network

57Sedan · 10-29-2014, 06:47 PM

Hello,

I'm looking at buying a project 56 GMC half ton that is sitting on a 1961 chevy half ton chassis. I would like to lower the truck as much as possible, and I'm concerned that the factory spec track width on the '61 might be a problem. The '56 normally has a track width of 60.5", whereas the '61 measures about 63 inches, or so the internet tells me.

I would hate to be in a situation where huge (expensive) changes are required to tuck the front wheels in a bit. Should I stay away from this one or should this problem be solvable with wheel offset or something else that won't break the bank? I really like the other upgrades that this chassis provides, but don't want to be limited in terms of getting the stance right.

Thanks so much for any help!

mr48chev · 10-29-2014, 07:35 PM

I don't think that you are going to do much with that 61 torsion bar suspension. You can crank the bars down and lower it some but It's been 30 years since I've worked on one of those and I can't remember if they could be bagged. I think you are going to find that there is no free lunch on that one.

Since you haven't bought it I'd be under it checking things out real close as it may already be a cobbled together mess. I'm not trying to bad mouth the truck but some guys who did those frame swaps in the past did them pretty crudely and you need to check to see if it was done right or just thrown together.

47 Fasttoys · 10-29-2014, 08:02 PM

FWIT, my COE had a factory track width of 61.3" I have replaced the chassis with a late model with a track width of 65". The point being the factory track width leaves a bit on the table for wider wheels. Because track is measured at the center of the tires the off set per side is only 1 1/4 " in your case. I would think you would be fine but the torsion bar system is a whole different issue. I have seen many an F-100 with the Plymouth torsion front end on them and it works very well. Worst case you could but some negative off set wheels.

Rob

57Sedan · 11-04-2014, 01:41 AM

Thank you both for the help. I took another look and the cab and front of the bed are sitting on 3" spacers which is not ideal for me. The truck is fantastic otherwise, so I've decided to pick it up and have sourced a 55 swb chassis to swap everything over to. I might see if I can cannibalize the '61 frame for it's trailing arm setup and move them to the '55 too.

Thanks again I appreciate your comments!

10-29-2014, 06:47 PM	#1
57Sedan Registered User Join Date: Oct 2014 Location: SF Bay Area, CA Posts: 10	Track width question - '56 3100 on '61 chassis Hello, I'm looking at buying a project 56 GMC half ton that is sitting on a 1961 chevy half ton chassis. I would like to lower the truck as much as possible, and I'm concerned that the factory spec track width on the '61 might be a problem. The '56 normally has a track width of 60.5", whereas the '61 measures about 63 inches, or so the internet tells me. I would hate to be in a situation where huge (expensive) changes are required to tuck the front wheels in a bit. Should I stay away from this one or should this problem be solvable with wheel offset or something else that won't break the bank? I really like the other upgrades that this chassis provides, but don't want to be limited in terms of getting the stance right. Thanks so much for any help!

10-29-2014, 07:35 PM	#2
mr48chev Registered User Join Date: Jul 2007 Location: Toppenish, WA Posts: 15,344	Re: Track width question - '56 3100 on '61 chassis I don't think that you are going to do much with that 61 torsion bar suspension. You can crank the bars down and lower it some but It's been 30 years since I've worked on one of those and I can't remember if they could be bagged. I think you are going to find that there is no free lunch on that one. Since you haven't bought it I'd be under it checking things out real close as it may already be a cobbled together mess. I'm not trying to bad mouth the truck but some guys who did those frame swaps in the past did them pretty crudely and you need to check to see if it was done right or just thrown together. __________________ Founding member of the too many projects, too little time and money club. My ongoing truck projects: 48 Chev 3100 that will run a 292 Six. 71 GMC 2500 that is getting a Cad 500 transplant. 77 C 30 dualie, 454, 4 speed with a 10 foot flatbed and hoist. It does the heavy work and hauls the projects around.

10-29-2014, 08:02 PM	#3
47 Fasttoys Registered User Join Date: Sep 2013 Location: Westminster, SC Posts: 933	Re: Track width question - '56 3100 on '61 chassis FWIT, my COE had a factory track width of 61.3" I have replaced the chassis with a late model with a track width of 65". The point being the factory track width leaves a bit on the table for wider wheels. Because track is measured at the center of the tires the off set per side is only 1 1/4 " in your case. I would think you would be fine but the torsion bar system is a whole different issue. I have seen many an F-100 with the Plymouth torsion front end on them and it works very well. Worst case you could but some negative off set wheels. Rob __________________ My '47 C.O.E build

11-04-2014, 01:41 AM	#4
57Sedan Registered User Join Date: Oct 2014 Location: SF Bay Area, CA Posts: 10	Re: Track width question - '56 3100 on '61 chassis Thank you both for the help. I took another look and the cab and front of the bed are sitting on 3" spacers which is not ideal for me. The truck is fantastic otherwise, so I've decided to pick it up and have sourced a 55 swb chassis to swap everything over to. I might see if I can cannibalize the '61 frame for it's trailing arm setup and move them to the '55 too. Thanks again I appreciate your comments!



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