[decooney]

Hi Roy,
I had quad Carrera 275lb springs on my Unique and the were pretty good for overall. My ERA has 300 or 325lb IBOC springs in the back I believe, and I'd have to recheck when I get home this evening... Let me recheck that again.

One critical factor is to measure the ANGLE of the mounting points. For example, when the car is sitting on the ground, is the top of the shock at a 1:00 or 2:00 type angle? Every bit of lean changes the mechanical advantage and changing the effective spring rate. The more your lean the shock, the softer the ride gets; even just an inch makes a noticeable difference. So, if you rear was narrowed to fit those wide wheels on a Butler, you might be more more verticle now if the mount points were not changed above. I believe Aldan will want to know this angle if you can estimate it for them.

Also, there is a another critical factor to measure for when plannign this with the shock builder. While the car is sitting on the ground, fully loaded with at least a 1/2 tank of gas and one passenger in the car, be sure to measure the distance from shock mount eyehole to eyehole. This will give Aldan an idea as to what height shock you really need if the car is lowered. As I recall, it was fairly low in the back. If you fail to do this, it's possible you could wind up with shocks that are too long, and they will bottom out on sharp bumps. We ended up having to replace 3 different sets of front shocks on Uniques because they were too long and bottoming out once lowered 1".

Somewhere around 275lb to 325lb would be good for the rears. I would agree that 300s would be good, if you shocks have plenty of ride adjustment. Aldan will definitely know if you give them those measurements too. Good Luck.