Leaf spring

[Jim C.]

I just ordered a 9 leaf from Detroit Spring then I saw they have a 6/3 spring. Did I order the wrong one for my 63 SHP?

[Lawrence M.]

Re: Leaf spring

Hi Jim,
63 used a 9 leaf spring where all leafs were curved. The 6/3 had 6 curved and 3 straight. I believe the 6/3 was used from 64 until about half way through the C3 era.

[Edward J.]

Re: Leaf spring

I agree with Larry, 63 is a one year only spring. 6/3 spring is starting in 64.

[Joe L.]

Re: Leaf spring

Hi Jim,
63 used a 9 leaf spring where all leafs were curved. The 6/3 had 6 curved and 3 straight. I believe the 6/3 was used from 64 until about half way through the C3 era.

Lawrence and Jim-------


Yes, the 1963 "all-curved" 9 leaf spring is a single rate spring. The "6 curved/3 flat" spring used for 1964 through 1974 is a progressive rate spring.

However, aside from the originality aspect, you can use the progressive rate spring on a 1963. I expect that the progressive rate spring is an improvement. You don't think that GM went to the progressive rate spring in 1964 because the single rate spring worked just as well, do you?

[Jim C.]

Re: Leaf spring

The spring I removed turned out to be a 6/3. I liked the cars rear height and the ride itself. Seems I'm reading continuing to use an incorrect 6/3 may provide a better ride?
Should the rear height remain the same using a 9 leaf ? I seem to hear this can sometimes be a problem.
thanks

[Edward J.]

Re: Leaf spring

Jim, I have seen a few Eaton springs installed in mid years and they are very close to the original ride height. Just a note, the 6/3 Eaton spring is slightly different from the originals the leafs are curled up more than the factory and will take a small deduct during judging.

[Joe L.]

Re: Leaf spring

The spring I removed turned out to be a 6/3. I liked the cars rear height and the ride itself. Seems I'm reading continuing to use an incorrect 6/3 may provide a better ride?
Should the rear height remain the same using a 9 leaf ? I seem to hear this can sometimes be a problem.
thanks

Jim------


The ride height should be essentially the same with either the single rate spring or the progressive rate.