rust is the enemy. I had a cracked leaf in both packs of my 88 before I started the build. I assembled 2 good packs (with extra main leafs as AALs) out of 4 packs during the build. They survived just fine for the next few years of hard wheeling, rusty though they were. When I had the opportunity, I bought a set of rustfree packs from Florida.
Not sure if the Chevy packs will work for you. lots of variables in leaf springs. What particular Chevy are they out of?