[suville]

There are frame dementions in the Factory Assembly Manuel, and to check for "square" you measure ( a helper is critical here!)from a point on right or left corner location in an X pattern front to back. You will need to use a reference point that is the same for each side front to back, your measurement should be within 1/16-1/8 inch if more than that your frame is what is refered to "diamond" and you will need a frame shop to rectify this condition. When assembling from frame off you need to loosley mount cab,box,core support and front fenders. Start with the cab as centered in its mounting holes as close as possible and go from there, once the cab is mounted everything else aligns with it and you may need to shim in areas to get everything to line up,dont worry about the core support until you have the fender and door line ( align the door gap to cab latch pillar and along rocker) as you want it and then you may need to shim the core support mounts. PAITENCE is the key here and nice even body lines is what seperates a good job from a hack job and if youve ever looked at the top builders you will notice that is very evident in their product. I have spent many hours cutting,welding and fitting to get as close to "perfect" as humanly possible. Unfortunately when many people see these"copperhead" trucks and think they will build or have one built they have NO concept of the many hours spent to get nice body lines that they NEVER came with from the factory. As an example just look at the fit of the cowl cover like socks on a rooster.Hope this helps ya somewhat.