[74proii]

Update to the problem: I got off the QA1 tech support line, as a few people in recent weeks have run across the problems we have been discussing So putting it in speck form.

Mustang II stock coil spring like MOOG p/n 8556 The free height is 13.81 inches and the outside diameter is 4.68 inches. 364 lbs/inch spring rate. Vehicle curb weight of approximately: 2660 lbs | 1206.556 kg
As I recall, most CRii’s seem to be at or near 2280 lbs. ish
As far as single or double adjustable coil overs it mostly up to your choice. Depending on which spring height the overall assembly will look like pics most people are used to seeing, the other way the assembly looks more like a strut with the spring mostly towards the top.
QA1 recommends that for most of the “Cobra” guys either run the Ultra ride for best all round performance, or the Aluma Matic Series, not the Stocker Star series most people buy. The other factor of course, is the bushing size. Mustang II sock being the 7/16”, and most aftermarket being 1/2”.

So for the stock like MGM bought would’ve been the “MS302-0860” length should have been fine the longer variety sleeve being p/n a “401” for example a ultra would be “GS401” for single adjustable, “GD401” for dual adjustable.
Per their guide axle weight 1350 would be a 375lbs spring rate, 1350-1525 would be a 500 lbs spring rate, a 1526-1700 axle weight would be 600 lbs. It seems that the majority prefer a “350” lbs spring rate.
Stock coil over from “ms302-08600” kit : spring 7.88” compressed, 11” extended overall
“gs401” spring 8.63” compressed, 12.88” extended overall
(forgot p/n) spring 9.63” compressed, 14.5” extended overall
The 401 series should gain close to 1” in suspension overall height.

Sleeves: 7/16” (1 each) p/n 9035-143
Sleeves: 1/2” (1 each) p/n 9035-113
Snap rings common to both (1 each) p/n 9007-102

There are 10”’ springs available I believe the p’n’s are as follows I might have got them wrong, we talked a lot of numbers.
10” spring “10MB350” ?
8” spring *MB350”
If anyone has any different or other data, your input would be appreciated. Thanks again to “Tate” from QA1 tech support (extension "443”)