I had posted this ongoing mess earlier stay away from blue moons control freak upper and lower arms they will not work with stock coil spring , lower arm has interference and bushing issues so I would not recommend the coil over either I have returned mine and am going with t.c.p. arms the owner of blue moon still refuses to acknowledge their a bad design even though I proved it to mustangs unlimited and got a refund these will be an issue on all 67 -70 mustangs and cougars