I 2nd ECE. Top notch quality and they really know these trucks. They have a superb reputation and are well regarded on this board. Take a look at their website
https://www.earlyclassic.com/. They have a great 4"/6" drop kit that a lot of people use. For the rear on a 5"/7" drop, the max drop springs you can get are 6" so you'll need a 1" block to get to 7". The front is easy with drop spindles and springs. Another great addition while you're at it is front and rear sway bars.