vibration when I step on my brakes...!

[Aquiles]

Hello everyone, I need some help/advice... I have a 1996 1/2 ton, C1500 short bed, I am having an issue that when I am going over 40 mph and I step on the brakes the truck vibrates like crazy, I attacked the obvious and changed the rotors and new brake pads but the problem persisted, I checked the ball joints, bushing all the tie rods, pitman arm and anything else I could think would cause it and couldn't find the culprit , this weekend I replaced the the upper and lower control arms with JDM tubular with a 3" drop, I also installed original height moog springs since I had cut the original ones, I also went ahead and replaced all of the steering linkage with all moog parts, I have yet to drive the truck because I did not replace my shocks and am waiting for them on order as well as urethane sway bar bushings since those were shot too, I have read a few threads and talked to a few people that were never able to fix the issue no matter what they did, I should be able to get it back on the road by the weekend and get it aligned with hopes that this solves my problem, any thoughts?