Moog coils FYI
 

My 67 had original front springs with 2.5" drop spindles. I was having some issues with the driver's side dipping more than the passenger side on severe whoop de doos. But it sat level all other times (could have been my imagination?)

Anyway, I like the stance, so I decided to go with stock replacement coils from Moog. PN 6082 $77.30 on Amazon. The install was straightforward per instructions available anywhere.

Springs compared - identical
Attachment 2438251

Going back in:
Attachment 2438254

Before starting ride height (old springs):
Attachment 2438252

After 20 min of spirited driving (new springs):
Attachment 2438253

It is almost exactly the same ride height. I am happy with the install. Is it any better? Maybe. I feel better driving it and it didn't seem to dip as before. Could be real improvement or could be euphoria of doing something on the truck. It basically shows that springs don't wear out, they either get over extended, over compressed, or hurt some other way. Otherwise, it appears they last forever.

Re: Moog coils FYI
 

To get a feel for the load, what engine trans are you running?

I have a 52 body on 64 frame with factory springs. It droops on one side but I corrected that by clocking one spring slightly. In the middle of swapping to slightly heavier engine and may need new springs but I don't want to change the ride height, I was eyeing the same moog part number

Re: Moog coils FYI
 

My truck has a 6.0 ls and 4L80E trans. SWB.