Any of you know the stock spring rate for a 68 Cutlass Supreme 4dr Holiday Sedan w/AC? Need to replace front coil springs and debating between Moogs recommended 5374 vs 5450. Looking for tighter handling and something to balance my rear air shocks.

5374 - Spring size: Inside Diameter 4.090", Bar Diameter 0.671", Installed Height 12" Load: 1886lbs Spring Rate: 317lbs

5450 - Inside Diameter 3.62", Bar Diameter .69", Installed Height 11.5", Load: 1642lbs, Spring Rate: 450lbs

Is 317lbs a bit too soft? Thanks!

 

Hey Buddy: I have not been able to find the spring specs for all the differnet options that were offered, but the AMA Specs for this base model (34269 I believe - you may want to confirm that) call for a SAE 6290, 11.3 in ride height, 3.60 ID, .588 diam length 127.0. spring rate of 280. The factory AC is going to add another 122lbs.

 

What engine do you have? 280lb without AC or 310lb with AC are pretty close factory values with a 350 engine. A 455 would be 310 and 335 respectively.
These are all standard-ride springs, which gave a very smooth ride.

FE2 springs were 435lb and were offered for handling performance on the 2 door models. Moog's 5450 is the FE2 replacement and will give better handling but less smoothness. I have them on Lady and the ride is still not harsh and choppy. I think you will be happy with those.

 

Hey Rob: what kind of ride height did you get with those 5450s? Can you point me to the spring specs for the the different spring codes for 1970?
Merry Christmas, Peter

 

I installed the 5450. What a difference they made on my ride! Handles much better. Raised the front sagging springs quite a bit. I can take a photo and show you in a couple days if you'd like.

 

I would love to see some pics.