Spring Rates and Specs

February 10, 2007, 08:01:08 PM

Hi,
I have been so bored today I was able to find some spring info some would be interested in. This info was from around 86, so I don't have the specs for the 87 and 88.

Stock Turbo Coupe with front code 1 is tag TAA that is a 425lb/in with 1750 load rate, code 2 is tag KAC that is 425lb/in with load rate of 1836. The rear code J with tag JAD that is 200lb/in with 963 load rate, code 3 is tag LUK that is 200lb/in with 912 load rate. Those were the most popular springs used from 83-86. The rule of thumb in chassis engineering was every 150 lbs in load rate subtracted from the factory selected springs the front would lower it 1/2" in the front and every 50lbs of load rate subtracted from the rear would lower that 1/2".

Spring set M5300B is tag MOG that is 435-530lb/in with load rating 1635 in the front and tag MIB in the rear with 200-300lb/in and load rating 587. These are production springs from a 85 no option Mustang V8.

Spring set M5300C is tag SAD that is 650lb/in with load rating 1461 in the front and the same rear springs as the B set. The fronts are production 84-85 Police/Taxi LTD front springs .

Spring set M5300D (for the Thunderbirds) used the front springs from the B-kit with tag MIN in the rear with 200-300lb/in and load rate of 732. The rear springs are production 85-86 Mustang GT Convertible units.

The HOT set-up was never offered for the Birds because it required Konis or Bilsteins to control the rebound, and at that time most people just reused the production shocks and struts. Using these springs with the production units made the car handle worse than the stock set-up. Those springs were the fronts from the C-Kit and rears were tag # CAZ 251lb/in and load rate 810 used in the 84-85 LTD LX. It lowered a stock TC or V8 about 1.5" all around.

That rear spring CAZ has not been in production for about 15 years and carried a service part# E3BZ-5560-C. The closest I have found is for a 99-04 GT that is part# XR3Z-5560-BA with 210 lb/in and load rate of 798. I will be installing a pair of these along with some the C fronts this spring using a pair of 03 Cobra front struts and pair of NOS rear T-Bird Bilstein shocks.