Don't want to get into a pissing contest with Dodgeboy, but the '88 up Chevy long hangers I have here use metric sized bolts, slightly larger than the original Dodge ones, so I am THINKING (I know, dangerous) that longer shackles for the earlier, '73 to '87 style GM pickups might be the right size.

Though, I haven't done it.

I had my leaves de arched instead ... not saying it's the right or only way, just how I did it.