3 1/2" Standard Length OEM style manual Mustang Rack Bumpsteer Kit is used for the OEM style manual rack and pinion (9/16-18 UNF) and standard length79-93 (13") lower control arms. Our kit eliminates unwanted bump steer created when chassis adjustments are made. The kit features grade 8 hardware and FK JM series rod ends. You can not find a higher quality kit anywhere for the money.This kit requires that you drill the tapered hole in the steering arm to a 5/8" hole.