1969 DART CUSTOM FULL RESTORATION

It'll be fine. The tram does the same thing as a tape measure, just fixed. A tram or tape works 2 dimensionsally. The centerline and datum take vertical relationship into the equation (3D). Basically an AB(intersecting circle) measurement with the CD measurements factored in to determine height relationship.

If you're off a bit on the front you can adjust your K-frame orientation. Either shimming for height/level, or elongate the holes for orientation to centerline. You can still pull caster numbers, don't worry.

In the rear just keep it straight. Your new floors aren't gonna match the originals. As long as it's straight the height and pitch don't matter. The only thing it will effect is possibly pinion angle, and that's easily fixed.