I put four new springs into mine also...and my left rear sits a little low like yours. Front is perfectly level. I can say with 100% confidence that NOTHING is bent. We tram-gauge measured the heck outta every inch of this thing in the process of installing new frame rails, weld-in subframe connectors, solid body bushings, etc. The work was done with the car clamped firmly to a Car-o-liner frame jig...which means we not only x-measured and straight measured, but we also measured everything up & down off a perfect plane from every corner of this car...both with and without subframe installed and eventually welded permanently to the unibody. And my buddy who has straightened unibodys for a living for 25 years, and who has structurally rebuilt about 20 first gen F cars in his lifetime, assisted me with the whole thing, and without a doubt this car is now officially straighter than it was when it left the factory...I bet we spent 30 to 40 hours in measuring time alone over the course of this basket case project...
Yet it leans a little in the rear only. About 1/2" difference from wheelwell to ground. I blamed my new springs for being slightly off balance, but I'm not positive. I think the only way to confirm is to swap my rear springs left to right. Not real interested in the hassle...
So I now count that at least FOUR of us, in this VERY small community, over the past few weeks, have mentioned our Birds sit a little lower in the left rear than the right rear? I find this all very interesting, and FAR too coincidental...
To answer your very original question, indeed factory setup these cars look like a boat taking off...rear low/front high. I didn't care for it and leveled mine out. My replacement rear springs were ordered in a heavier duty version, and they sit higher than stock and are VERY very stiff, which I like.
If you ONLY want to raise the rear a little bit from where it is now, and keep your springs, the easiest/cheapest/fastest alternatives for you are: 1. Longer shackles, or 2. Air shocks.
