My new to me 67 C10

[Nitrodan]

As of last night Im the new owner of a 1967 C10 1/2 ton long bed
This is my first C10 waited until I was 70 to get one
So the truck looks like its been lowered a little my question is because I don't know much about the truck and the people I bought it from did not know how much it was lowered I want to start over new lower springs and it needs shocks so what is a good spring height to start with With out having to C notch the frame at this time At this time it has 6 lug wheels I probably will want to go to 5 lug later
Thanks more question to come