It was admittedly a long journey to get the right gas struts for the GT. Length is more important than I had originally thought as well. In one iteration we were short by only 6mm and thought it was OK but it translates to quite a difference in clamshell opening. We went back to the drawing board! Ford has some car assembly best practices that bled through to the GT. (If you remember that early 2005 cars had metal clips hiding the body line on the upper part of the clamshell... hiding exposed body lines was a best practice.) Another best practice was to speed assembly and prevent errors. The lower ball is an 8mm ball and the upper ball is 10mm - thus insuring that the springs would always be mounted rod-side down. Note: This is always the correct orientation for a gas strut.
The GT clamshell struts have a particularly high charge and use a larger diameter rod. Stabilus highly recommended a 10mm ball-end. More importantly, to get the right length and preserving the full (OEM) opening height of the clamshell, the cylinder is a few mm longer. While this is great to achieve full opening, at the minimum (fully closed) length, you should still have a couple of mm of rod length exposed for maximum longevity. The GT lower ball stud is in a nutsert and easy to un-thread. We include a small bracket that moves this location fractionally rear-ward to accommodate the longer cylinder and on that bracket we have a 10mm ball stud.
