I did the same as Ron.
Think about scaling the car on all four corners, it's well worth it !
I thought my setup was real close, boy,..... was I wrong.
I started off just wanting to replace the coil overs and lower the rear ride height, then included getting new heim joint's on the rear, so I borrowed a friends electronic weigh scales. Man, each corner was way different. I made a threaded rod strut tool with heims that mounts to the shock mounts to get the height I wanted, then measured what length of springs I needed. Worked great. Even with a BB, the percentage now is 48%-51%.
For fun and as a test, I may take the cockpit adjustable,....shocks of our sprint car and hook them up to the cobra. That way, no matter what person I have with me or what road condition I'm driving on, I can adjust the shocks on the fly, without stopping the car.
__________________
Thanks,
Kevin