FWIW, I used the 5401's with Viking Coilovers fronts on my Pro touring GS as they sit 1" lower than stock. They are replacements for 68 and 69 GTO's and have a 129# rate.
RA showed the moog 5385 as stock. I gave them a try. I would agree pretty stock. Typical skylark stink bug look. The frame and body are basically level but because of the quarter design it looks way low. I will be changing them out we’ll see if this works.
It is down but not sure what springs are in front. it actually measured less than a stock one I compared it to. Measures 9.5” from bottom of frame at weld front and rear.
Hey, I wanted to add to this old thread, I ran across it when picking my springs and I feel it helped. I went with the 5379’s along with the KYB gas adjust shocks... with the coil spring insulators doing the whole rear was about $115 and an hour of time... not bad at all for the improved stance and ride. I still had stock shocks and coils so you can imagine how rough and saggy it all was. Here are some pics... I gained about two inches in the rear... I’ll repost next year to see how they have settled after some time. Tires are 235/60R15
I still like the lift they provided. Rear tires are 235/60 R15 and the top of the rear wheel well is 25 and 1/4 inches off the ground. I don't feel like they have changed at all (or settled) over the last 10 months. Here's an updated picture.