Ladder bar back halfed, iv used the trans crossmember and got it aligned, but if i try another location like the front leaf spring mount i get almost a 1/4in difference, where else is a good reference to measure from ? i also have Bobs Pro Fab tube and rack K-member.

Check squareness from the trans crossmember to the ladder bar crossmember. If square, go from the ladder bar crossmember to the rear axle.

that was how the ladder bar X member was measured and installed off of was the tranny X member, im just getting picky about the settings making sure.

Are you going in a X for measurements? That will tell you if square. The old leaf spring front mounts might be twisted up if you were racing it with leafs in it.

^^^that^^^ cuz a parallelograms' legs will measure out equal but ain't square

Every alignment guy I've worked with suggests eyeballing the rear for alignment. Roll the car straight forward (enough to get the car to settle) then look for an uneven reveal on the rear tire sidewalls by looking from the rear down each side of the car. Not very scientific but when you consider all the potential variables "square" is a relative term.

i have a laser in the end of a level, lay it across the rear sidewall shooting at the front. measure from where the laser lands over to the end of the spindle, on each side

That's a great idea!

This is how I do it. But, the rear has to be center or this still does not work.

thats how i did mine as well.