The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - 55.2-59 57 GMC 100 vs 57 Chevy Question?

dsraven · 02-16-2016, 11:00 AM

the chev and gmc frames are the same as long as they would both be 1/2 tons that you are comparing. the biggest difference is the dash and the grille areas. the front fenders have a dimple in them to accept the gmc mustache grill wrap around part so that would be one thing to watch for if you need to swap out a fender or something. the mustache covers the hole where the chevy marker light would be. the gmc has a hole in the hood out front where the emblem goes in. the grilles are obviously different, otherwise the cabs, boxes, frames etc would interchange. just a note on the front end swap, a lot of guys will set the axle centreline ahead of the stock axle centreline because with the sweeping angle at the rear of the front fender wheel opening the wheel looks like it is stuffed into the rear of the fender when you lower the truck. if you stay with a stock height that wouldn't be a concern. i think I set mine an inch ahead, maybe an inch and half. also, there are bolt in kits available now as well so a lot less hassle figuring out angles etc and then welding it all in hoping it is correct.make sure to talk to the tech dept about support and get a detailed instruction on how to install and get angles and measurements etc. I got my kit from TCI and had many problems because (little did I know) they actually had a mix up and shipped the wrong crossmember to me. I made it work but the tech dept was basically no help and I just researched the net till I found specs for a mustangII and then applied that to my set up. plan on purchasing a digital level and laser. the level so you can get accurate details instead of eyeballing a glass bubble builders level and the laser so you can get the frame nice and straight before you start.
good luck, keep us posted with pics of what you are up to.

02-16-2016, 11:00 AM	#6
dsraven Registered User Join Date: Nov 2010 Location: calgary alberta Posts: 8,490	Re: 57 GMC 100 vs 57 Chevy Question? the chev and gmc frames are the same as long as they would both be 1/2 tons that you are comparing. the biggest difference is the dash and the grille areas. the front fenders have a dimple in them to accept the gmc mustache grill wrap around part so that would be one thing to watch for if you need to swap out a fender or something. the mustache covers the hole where the chevy marker light would be. the gmc has a hole in the hood out front where the emblem goes in. the grilles are obviously different, otherwise the cabs, boxes, frames etc would interchange. just a note on the front end swap, a lot of guys will set the axle centreline ahead of the stock axle centreline because with the sweeping angle at the rear of the front fender wheel opening the wheel looks like it is stuffed into the rear of the fender when you lower the truck. if you stay with a stock height that wouldn't be a concern. i think I set mine an inch ahead, maybe an inch and half. also, there are bolt in kits available now as well so a lot less hassle figuring out angles etc and then welding it all in hoping it is correct.make sure to talk to the tech dept about support and get a detailed instruction on how to install and get angles and measurements etc. I got my kit from TCI and had many problems because (little did I know) they actually had a mix up and shipped the wrong crossmember to me. I made it work but the tech dept was basically no help and I just researched the net till I found specs for a mustangII and then applied that to my set up. plan on purchasing a digital level and laser. the level so you can get accurate details instead of eyeballing a glass bubble builders level and the laser so you can get the frame nice and straight before you start. good luck, keep us posted with pics of what you are up to.