I have 68 (67 shelby clone, no pics yet) sits perfect.
globalwest rear springs ,no lowering blocks needed (almost too low),
up front I did the shelby drop, with all global west
suspension, and 620's, I did cut the 620's but I forget how much.
cut 1/4 coil at a time, dirve around let it settle, and repeat if neccessary.
dont forget when you change the ride height up front it needs to be re-aligned so just go around the block so you dont F-up your tires, bounce the front end up and down too.
do your front first until you're happy , then use lowering blocks if you have to.
Invest in some roller spring perches, best investment i've ever made.
I'll try to post some pics soon