Be careful to measure where the spring eye mounts. Mine had been broken and rewelded when I got it, it dog-legged pretty bad, finally found the problem.
Dog-legging is going sideways driving down a straight street - looks funny. The offset of the body from straight was almost 4 inches!
The front spring eye bolt was only 5/8" to the rear of where it should be, - it made that much difference. What happens is the axle gets set set back by that much, making front and rear axles not parallel, result is a sideways cant --- dog-leg. A little bit of inaccuracy goes a loooong way.
Make your measurements "X" style. Measure from a point on right front to left rear axles, then from left front to right rear axles. "X'ing" makes for a more accurate measurement - as long as the axle is centered like the front one.
I had to make up a couple long sticks like 7 foot calipers as guides.
It was a real pain getting it right, but after I compensated for that little 5/8" error it ran straight and handled better - it was worth the effort (and stopped the laughter.)