Yes K"s are all the same from Contol arm to strut rod flange length
The shorter rods are for the two piece are always coarse thread on bushing end see picks above
No matter what your car is used for Bushings should be tightened at correct ride hieght when alligned.
I use early SS rear springs . Everyone that uses these knows they make the car lean after installed. The reason is to accomendate for torque to the left rear. On most of the older SS cars using these springs If you look at picture you will notice their front wheels do not drop out on launch. This is because they either are cabled up or have Upper a arm bumper extentions. which helps eliminate bump steer
Preloading the right rear does help with those uneven SS springs. I am not going to get into why but here is what I do.
First most mopars are not built or welded together correctly. How many of you go to burn out contests and see cars that want to spin around when doing a burnout. this also effects the launch.
Where the leaf spring bracket bolts to the front of the car. The flat surface with the four holes where the studs go through. Alot of cars especially non perfomance models that were auto/open rear cars were not straight. Mine was 1/2 inch off. and seen worse. An easy check is where that is welded to the frame rail there is a tab that is welded to the bottom of the rail. In front of that tab is a hole about 3/4 inch . Measure from that tab to the hole. you will see a difference if your car is not built straight . Mine was 3/8 difference from side to side. you can shim the short side back to correct this. Measure from K-member mounting bolt back to the pad to get the correct thickness of the shim needed. I made a 1/2 inch plate with four holes out of aluminum and put it in front of that spring that had to come back. After putting in longer studs.
Then preload , With car setting on level surface jack the car in the center of the rear. This lets the car sit on three points . adjust your front bars to sit approximately 1/4 inch above lower Control arm bumpers. Make sure your bumpers are new or the same hieght. This levels your suspension without sitting on the uneven SS springs. When you leave the car down the car will lean to the left front. Jack weight to the left front with the bar adjuster until both rubber bumpers are the same. Usually the bumper space will raise to about 1/2 inch before it levels This differs from car to car. somethig you'll have to play with. Always do this without the stabilizer bar attached. Then reattached it when done. Remove left link from stabilizer bar when drag racing for even transfer.
I owned several Dana cars that used these springs from the factory. and always used this method on those cars also. It works for me.
Put a spacer under upper a arm bumper to shorten the distance the front drops out when launching. If yo have a deep pan or headers that hang. On a drag car you can add a spacer under the lower arm bumper just to make up the space between the frame and the rubber bumper. This will prevent your pan or headers from scraping when coming back down. six cyl. bars cause this travel to be excessive and quicker but are weak coming down. mine still sqashes the rubber and just touches the one tube I have to move up. Poly bumpers are stiffer and give more control but you will have to keep an eye on them .They do not take as much abuse as the rubber. I have poly on mine and have spares.
My front shocks are 90/10. my backs are QA-1's I have the right rear 2 clicks tighter then the left But again this is what works for me. I do not road race my car. My front wheels are 3 inch the rears are 12 inch. With a spool it doesn't like to turn. I run a tightened up clutch suregrip on the street. One reason I stayed with a 8 3/4 easy gear and chunk change for different uses.
I will be going to Cal-tracs soon with monos. This will probably change things for me and then I will be asking some questions.