55-59 mustang ii crossmember measurements

[Jbm1956]

Are there any builds or posts on here that gives the step by step measurements and install for the 55-59 mustang ii crossmember. Thanks guys. It looks like you measure 20 7/8 from the front shackle bolt but not sure if thats the best way or if there are different ways and whatever else is involved. I appreciate all your help guys thanks so much