The wishbone brackets were made from ½ x 3 inch cold rolled steel with a 5/8ths hole drilled and chamfered for the mounting bolt. I build a little heavier than some , but I would rather depend on a 5/8ths inch bolt than a ½ inch bolt when my life is at stake. To mount/tack these brackets to the frame, I use a small piece of 1x1x1/8 angle c – clamped together and the wishbone mounted so that I can adjust the angle from the frame to the axle.
With the angle clamped to the bracket, I then use a large clamp to clamp the assembly to the frame and adjust the angle to the axle. I will usually bring the rear of the wishbone bracket to the front of the firewall and this seems to bring everything into proportion. When everything looks good, then I tack the bracket to the frame and use the same procedure on the opposite site.
As you can see, the stock wishbone is to long and must be cut. Also notice the front wishbone bracket to the axle is at an angle. This is because I set the axle at a 4 to 6 degree angle for the caster angle. I need the wishbone shorter so that I can raise the wishbone up to mark the axle in order to cut it at the correct angle.
With the wishbone cut at the proper angle, I block it up to where it is centered or put where I want it , and then tack it in place. I use the same procedure and set up on the opposite side to insure that both are as close as possible.
With all the spacers and clamps removed, I can check to see that everything is lined up , angled, spaced, squared away and that both sides are as close as possible. If not, then I would cut the tack loose, reset and re tack.