All OEM frames have holes punched or drilled to mount various components that will be the same distance front to rear, spring mounts, shock bracket mounts, engine mounts, etc. On the passenger side, measure from the center of one of the spring mount rivet heads to any punched hole on the front of the frame. Write it down. Now, measure the same point to point on the driver's side. Write it down. If they're close to the same, within a sixteenth inch, you have found the proper front holes that match each other side to side. Now, string your tape from the LR point to the RF point, diagonally. Write it down. Now, string your tape from the RR point to the LF point, diagonally. Write it down. If your diagonal measurements are within 1/8 inch, you're ok to go ahead with this frame. If the measurements are off more than that, the frame has been tweaked. It will need to be put on a frame machine and squared or you will need to find a valid frame to start your project with.anyting but original said:I'm starting with just a frame leaf springs mounted "no axles" how can i find the wheelbase and the center of the wheels so that I can sub it and place my rearend any help?