Need some advice on rearend alignment

[OUTLAW]

Okay , here is the situation: Several weeks ago I moved my springs inboard and added SS springs. Before I did this I took some measurements diagonally from the factory alignment hole in the front subframe to the pin in the leaf springs. Both were the same (within 1/8th inch) which says to me that it was square to begin with.. When I was done with the relocation I measured again and tho my dimentions changed the readings were again 1/8th to 3/16th (factory says less than 1/4" is acceptable). Again this says square to me.
Now for the present situation, I decided to move the rearend back 1 1/2" for tire clearance in the front of the wheelwell. Measured precisely (and since doubled checked) and redrilled the holes for the front spring bushing bolt. Double checked diagonally again from the same 2 alignment holes to the pins in leaf springs and now I have a difference of approx. 1/2 " to 9/16". Nothing else was changed except the 2 front spring bolt holes- never even unbolted the rear shackles or shock plates. I have since then loosened them to see if it would settle back into specs ...nope! This don't make sense to me!
Now to verify this against my front suspension I meassured from the centerline of the front spindle to the centerline of my rear axles on each side. There I am dead on with less than 1/8" difference between the 2 sides....WTF! So my question is : would you go with the rear to front alignment readings or square the rearend up to the frame as it was before? My thinking is that you want the rear square to the front wheels to go straight and to hell with the factory specs. Your thoughts

 

[clhyer]

Does the car sit level? Almost sounds like one of the rear leaf shackles hasn't pivoted as far back as the other side in which case I would expect the car to sit a little high on that side.
Can you post a pic of what you did at the front mount. This sounds like an interesting mod.
Before starting the job you took your diagonal measurement. Did you also take the wheelbase measurement?
When taking the wheelbase measurement, did you use a string to assure plumb with the rear wheel?
Personally, I would want the diagonal measurement to be square.
Good luck with it.
C

 

[crackedback]

Get the car level and squared up. Drop a plumbob from the original leaf mount eye holes and something up front(A arm mount). Find the centers of both set of points front and rear, draw a line from those midpoints, that should be your centerline.

You can then make two criss-crossing arc using a string and pencil to get a line perpendicular to the centerline. Measure off of that line. It's really tough to get good measurements off the torsion x-member etc. This will get you a line that is close to the item you wish if square.

Make sure the centerline that gets plotted make sense. If the car was in an accident, bent up subframe could affect the C/L plotting.

A laser pointer/leveller comes in real handy to visually see the perpendicular lines coming off the C/L.

The tolerances on these cars was very sloppy from the factory. If you have the axle within 1/8", you likely good.