6"lift, front leaf spring length

[madcow75]

Hello I am Building a 1980 3/4 ton chevy and I want to put a 6" lift on the truck. I have everything requried to do a lift, sterring arm , shocks, and rear blocks but I was wondering what is the length of front springs required to do the lift. I have oem front 2 and 5 leaf front springs and I also have some 56" and 52" rears. Are any compatible with some work from my local spring shop re-artching them. Or could I go to the local scrap yard to get something that I could work with. Any info on the front springs would be greatly appreciated.