New to me '77 Silverado - Light blue original paint - 2 leaf springs!??

[Gribbs]

Greetings from Ontario, Canada...I've been on the site a while and I have just finished a 5 year long Apache build, only to find myself picking up a '77 a couple weeks ago. All original with great color and patina - I coudn't pass it up and now the '59 is for sale.
It has: 305/TH350 with a 3:07 or 8 gear. A/C not working, tilt column, drives fine and all gauges work

Question for those much wiser than I: It looks to me like the P.O. wanted to lower the truck and did so by removing leaves. I assume he just cut the front coils, judging by his method on the rear here.
I'd like to get 2 more inches of drop front and back. With only 2 leaf springs right now, what would be your suggestion to safely get two more drop? I did a short ride in the truck and the suspension felt fine enough. However, I also have a '74 shovelhead that I may want in the bed from time to time. Maybe I need some air helper shocks to pump up when that happens.....

Thanks for your help!

Gribbs