[Mike C]

GM built the trucks both ways. As a general rule, GMC came with leaf and Chevy with coil in the 1/2 and 3/4 ton trucks. But you find GMC with coil and Chevy with leaf. All C30 trucks were leaf.

On my '70 GMC C2500 I used ECE shackles to bring the back down more level but not lose any towing/hauling capacity. On my current '69 Chevy C10 leaf truck I used a DJM flip kit. Draw back to the flip kit is you don't have a lot of control of how much drop you get. On my truck is was just over 7" which may be more than you want...

I have 2 1/2" disc conversion spindles and 2" drop springs on the front for the look I wanted.

You can buy drop springs in different heights depending on how low you want to go. Leafs are just a lot more expensive than coils so make sure and know where you want to be before opening the old wallet.