Can anyone give me a measurement from center of spring perch to center of other spring perch on an 8 3/4 housing. I just installed MP XHD springs on my 73 with poly bushings and had a hell of a time getting them to go on, had to force the 2nd spring over about 1.5" to get shackle on. Not sure if this is normal as this is the first time i have replaced leaf springs. Thanks to all for your help.