Cutting progressive rate coils is tricky.  You only want to cut off the part that makes the least difference, but its going to increase the rate somewhat.

To clarify, if you cut progressive rate coils they will have a higher spring rate meaning a stiffer ride.  Cutting a non progressive coil doesn't have this effect; all you change is the installed height.  But progressive coils are wound such that the space between the coils changes coil by coil, so the typical formula used to determine spring rate doesn't apply.  By varying the distance between the coils progressive rate springs act as a soft spring initially to make for a smooth ride over minor bumps, but the spring gets stiffer the more its compressed so that it can still handle big bumps without bottoming.  Therefore, when you cut a progressive rate spring you are cutting off the side that has the softest spring rate, so that's going to increase the initial spring rate and make for a stiffer ride. 

Progressive coils usually do not have uniform coil radii.  If the radius varies on coils near the end(s) then it's a progressive spring. 

Ok. Drop first, check height, then cut FRACTIONS of coils if necessary. I'd start with 1/3. Not meaning to insult your intelligence, it can be tempting to not want to take it apart again, especially when compressing coils is involved.

Awesome thanks I'll keep ya updated on the progress. I can't wait my car should be done soon. I was even thinking about taking it in August if it runs really nice down to hot August night in Vegas that way I can get some driving in have some fun plus it's right on my brothers birthday.

6sally6 wrote:

Great shake-down run  before the October MS Bash in FWB Fla.
Hope to see ya there!!
I mean come on!!!!!! Who helps with your Mustang more.......your brother or...... "your Brothas" man??!!!
6s6

 
Actually now that you mention it my brother finally helped me out by holding the hood in place while I bolted her on.