im replacing the shocks and installing tubular upper and lower control arms and spring isolators so i figured i would replace the springs as well. interesting...so ur sayin that basically unless they are broken, cut, etc. then there is no need to replace them? i was just under the assumption that, like everything else on my car, the springs were worn out. also i was told to look into getting different springs to improve handling and so on. but it seems like all aftermarket springs are lowering springs. should i just stick with the stock springs?
Nope, stock springs
do not wear out. The isolators DO WEAR OUT! Get new ones!
As was mentioned, Mach1 rear springs with poly isolators will lower a
STOCK Fox about ~1/4" or less (5 speed, battery in stock location up front, no "extra weight" in the back from stock, etc).
Poly isolators don't compress. So, they raise a Fox
approx ~1/4" (+/- ~1/4").
So, if you "must" get new/newer springs, and don't want the rear lowered, then get Mach1 springs and use poly isolators.
Also, I strongly suggest that you measure your fender height before you take anything apart.
Check and set your tire pressures! It'll take a few minutes at most.
Then, do the swap. With new isolators (stock or poly)
the car will sit high for a few weeks! You'll have more drop with new stock isolators since the springs dig into them more. You'll have only a little drop with poly isolators.
Long term:
In the back, with stock isolators, you'll loose a little height over the years until the bottom isolator eventually "disappear".
In the front, the upper stock isolators slowly compress over ???5-10 years???. The front lower stock isolator will also isolator eventually "disappear". And that also causes you to loose a little height over the years.
Basically, even if you put on new stock isolators and your old springs, the rear of your car will raise
a little.
BTW: Since I have an '86 with fenders that aren't as wide, and I want to run 245's up front and 275's in the back, I do not want to roll my fenders (I like my
stock '86 body!), and I want better handling, I also keep the approx stock height for a GT (which is already low by OEM standards!).
Mustang 86 - Mach1 Springs
Hope the above helps!
Good Luck!