The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - 55.2-59 subframe question

dsraven · 03-01-2022, 10:37 AM

I have a 57 gmc but it uses the same rad support as a chevy truck, it's Canadian so maybe thats why? the GMC specific parts are like hen's teeth and the GMC sheet metal assembly stuff doesn't appear in the chevy manual I don't think. sounds like you have experience doing this sorta thing so I'm sure you have a plan and will get'er done. the frame drawings will be nice as they show how much drop the frame has from the cab mounts to the rad support mounts and also the dimension between those-fore to aft. the bumper mount dimension is another one. everything seems to be measured from the cab face as a starting point, which is the firewall. kinda like reading a blueprint, you gotta lot of math to figure out the dimension you need. I'm sure you have thought of this already but a new set of cab and rad support mounts would be good to have installed just so you can get stuff lined up correctly. there is a video on youtube showing how to get things lined up and gapped properly, it uses the drivers side front cab mount as a pivot point and shows how to rotate the cab from there to achieve proper alignment of the hood and fenders. it is "old man fixing stuff", google 55-59 gmc truck panel alignment, it's a few minutes of time that may pay off if you are new to these bodies.

03-01-2022, 10:37 AM	#26
dsraven Registered User Join Date: Nov 2010 Location: calgary alberta Posts: 7,837	Re: subframe question I have a 57 gmc but it uses the same rad support as a chevy truck, it's Canadian so maybe thats why? the GMC specific parts are like hen's teeth and the GMC sheet metal assembly stuff doesn't appear in the chevy manual I don't think. sounds like you have experience doing this sorta thing so I'm sure you have a plan and will get'er done. the frame drawings will be nice as they show how much drop the frame has from the cab mounts to the rad support mounts and also the dimension between those-fore to aft. the bumper mount dimension is another one. everything seems to be measured from the cab face as a starting point, which is the firewall. kinda like reading a blueprint, you gotta lot of math to figure out the dimension you need. I'm sure you have thought of this already but a new set of cab and rad support mounts would be good to have installed just so you can get stuff lined up correctly. there is a video on youtube showing how to get things lined up and gapped properly, it uses the drivers side front cab mount as a pivot point and shows how to rotate the cab from there to achieve proper alignment of the hood and fenders. it is "old man fixing stuff", google 55-59 gmc truck panel alignment, it's a few minutes of time that may pay off if you are new to these bodies.