HDK coil over system - spring selection

Buschi340 said

for stock K-Member. Have it already and also the qa1 shock multiple adjustable.

My question is about selectiong the correct spring. I know I have too weight the car. The whole car or just the front?
From that Point i can follow the qa1 instructions and calculate the rate with weight and angle...

But - can I have a longer length than the 12" Shocks to give more travel in expanding for weight Transfer ( drag race some times ). regular spring just longer or high travel spring? Hope that doesn't effect streetability too much?

what about springs with multiple spring rates they offer? any good or not recomendable?

car is a 72dart with 6.1 HEMI

Coil-Over Springs | Street Performance, Drag Racing & Circle Track Racing Coil Springs | QA1 Suspension

Click to expand...

One of the drawbacks of the coil over conversion with a stock K is the limited space available utilizing the factory pivot points and shock mounts. The 12" coilovers work with the HDK because of the relocated / lowered LCA pivot point....required by the rack / pinion

based on other builds, I think a good place to start with your application is 450lb springs.....I usually install them with all the weight (not in mock up mode) on the car as it will be driven.....put the car at the ride height you desire....(in the recommended ride height range of the shock mfg) and measure how far the spring compresses. It should compress approx 25-33%. If you have to crank the pre-load beyond 33% of the uninstalled spring height to get it in the mfg range.....you have too soft of a spring. If you do not have to crank the preload up to 25%....you have too still of a spring.