Mustang Spring Rates Tech

Tech Question - '66 Mustang Spring Rates

Mike,
I have a 1966 Mustang Coupe with a 200ci engine and 3 speed manual transmission. Not a speed demon by any account. The rear end is sagging so I want to get a pair of leaf springs from Eaton. I've heard nothing but rave reviews from the Mustang forum I frequent. I'm undecided whether to get the standard 85 or improved handling 110 rate. Price isn't an issue as they are both the same. My concern is how high the back end will set when installed. I'm assuming it will set higher with the 110's, correct? I'm not sure but I'm guessing when the car was new it set pretty level front to back. That's kind of what I'm looking for or maybe a bit higher in the back, but not a jacked up look. Please advise. - Don

Don,

No, your car will not sit higher in the rear with the 110lb springs. When more than one rate spring is offered for a vehicle such as your '66 Mustang, the springs are designed so the vehicle will sit at the same height with either spring.

Both the ML1435 and the ML1025 are designed to be negatively arched 1/4-inch when loaded to 610 lbs. This is accomplished by the springs having different free arches. The low rate 85 lb ML1435 spring has a free arch of 7.125 inches while the higher rate 110lb ML1025 spring has a free arch of 6.5 inches.

The early Mustangs all sat a tad lower in the rear than the front. Many customers request springs which will raise the rear 1-inch. Of course the choice is yours. - Mike