Body and Frame measurements

Dodge33 said
This is just a FYI.... alway's take in consideration, that these factory measurement dimension's should only be used, when you are using OEM used frame/body metal, as a lot of the aftermarket framerails/etc. and unibody support metal, do not have the locating hole's in the proper location, which does make it very difficult to use a factory specification measurement with using aftermarket stuff. We learned about some of this, from Jeff @ 521 Restoration's. Some of this info pertains to a B-body car only.

Sorry, but regardless of the parts used the factory measurements are the factory measurements. Most of the factory stuff is +/- 1/4" if you're talking frame rails etc. Body measurements can vary more than that even from the factory.

That said, it doesn't matter what parts you use. If you can't get the factory measurements with aftermarket parts, you need to fix the aftermarket parts, not use different measurements. Assuming the rest of the car is straight.