3/4 nuts work perfectly for that, and look nice. This lowers steering suspension in reference to the engine mounts that are hard on the frame rails. Applies a slight torsion bar load though.
The only engine mounts that are "hard" on the frame rails would be a motor plate..otherwise the mounts and steering are both bolted to the k-frame so shimming it down will do nothing except move it all...down. Get the right pan and make sure you have the V-8 center link
P.S. after looking at the pics,it appears to the V-8 center link. I would "mod" that pan with a few well placed hammer mods. Just my 2 cents
