I have the frame for my wagon sitting bare on my trailer ready to go to the sandblaster next Monday. Since it is easy to get at and measure, I took some measurements diagonally as outlined in the shop manual. What I found is that the corresponding diagonal measurements are 3/4" different at both the front and rear measurement points.

On the "front X" which runs from the body mount at the firewall to the body mount just ahead of the rear suspension mounting point, the diagonals measure 80 5/8" and 81 3/8". On the "rear X" which runs from the body mount just ahead of the rear suspension mounting point to the body mount at the rear corner the diagonals measure 84 1/8" and 84 7/8".

Is 3/4" difference enough to be concerned about? Since the frame is bare and easy to access, if I need to have some frame work done, now is the time.

TIA.

RichI I would make one more measurment.
By droping a line from the rad support and Xing to the front body mount you used in your orginial measurments, If it has the same deviation ( and i assume it will )+ and - .750 " as your other findings.
Head to the frame shop for a little TUG .
Spec's are plus and minus .250"
chevell sheel metal are a PITA to line up to beging with and a .750 off-set is tough to over come . IMHO

GL

I did make such a measurement and found a similar discrepancy but I didn't report it because the numbers may be a bit skewed. I simply measured with a tape measure from hole to hole. That works great on the other two sets, but in trying to do the same up front the engine cradle and spring pocket portions of the frame get in the way of measuring with a perfectly straight line.

I've already got an appointment at the frame shop. Bummer of it is the guy who sold it to me dropped $300 (his money, not mine) at a frame shop before he sent it to me. And they couldn't bother to identify and correct a .75 misalignment? I don't think I'd ever go back to that particular shop again if I were him.... In the end it's gonna likely cost me another $300 to make it right. At least I'm doing it now instead of when I can't get the body to fit on properly.

I also wonder if I should have the frame shop bend the front spring pockets down a bit since these old frames tend to sag in the middle making front end alignments harder to achieve.

Oh, and I also found in my shop manual that measurements off by more than 3/16 should be addressed. That's a lot tighter than I'd have thought.

The procedure depends on the type of Frame rack on how they attack the problem... but after the set up any GOOD Frame Tech. shoud also look at the vertcial measurment and use a measurment jig to check all the dim up down and sq.
your manual has the dim from the datum plane ./
I think I would take a copy along with me .as for
as for the tolerance he should be able to yank it to within an 1/8".

I know guys who worked at Parish Steel Reading PA ( later Dana corp) GM frame shop.
According to them , The frames were welded in a Jig with a final tolerance of .125 (1/8) in.
and got deviations for none critial location of up to .250

As for the spring pocket !!! IMO get it straight and true,, and assemble it with offset control arm shafts.. you'll get all the extra you need in your high performanc alingement.