1969 Rear Spring Rates?

[olympic69]

I may have this all wrong- but in looking at spring rates (rear) the Z28 shows a rate of 103, while other base models have up to 126 Lbs, while the 427 CI option shows a 4 leaf 126 Lb spring. I used the MOOG 6308 in my Z28 as a replacement, and additionally Mr. Pozzi recommends 125-150 rear rates- so why did GM choose to use such a "light" spring on the "HD" model(s), which would seem to make the car prone to oversteer?

[JohnZ]

why did GM choose to use such a "light" spring on the "HD" model(s), which would seem to make the car prone to oversteer?

It's the other way around - lower rear spring rate reduces rear roll stiffness, which reduces the tendency for oversteer.

[olympic69]

Thanks- I appreciate the response from a reliable source!

[BlackoutSteve]

I always thought monos were ~145in/lbs.. 4 & 5 leaves are naturally a heavier rate.