Hi Chris, great to meet you at the Brisbane Classic. Meant to have a chat with you but the day flew by - you looked busy too.
I drove an 85 and an 89 while in Brisbane. VERY interesting .
Firstly I should mention the famous 'Spring Rate' chart by Hib Halverson -
http://corvetteactioncenter.com/tech/c4/susp_chart.htmlit gives every spring rate from 84 to 96 (and much else besides).
The infamous 84 hard spring was (front/rear)102/87.5 N/mm
My 88 with Z52 , the softer option, is 93.1/39.9
BUT - 85, 86, 87 the soft option was a mere 51.8 on the fronts and the same 39.9 on the rear.
GM stiffened up the front springs from 88 to 91 then returned to softer springs so that by 96 the rating was 60/26.
That's why, when people talk about the harsh ride, owners of other years can't understand what we're going on about !
However, thanks to my recently re-valved Bilsteins, I discovered that I had the softest ride of the two vettes I drove in Brisbane.
Also, I had a soft ride while in Brisbane, the roads are so much better than here in North Queensland. I began to have trouble on the drive home at Mackay where the road deteriorated, by the time I was North of Townsville I was hitting humungeos bumps etc, got hit by the famous scud missile effect when near home, and it tore the lower shock absorber mount off it's rubber suspension (5 weeks old)
So I'm looking for the late model springs - 60.26Nmm either to buy or as a swap. My springs are fine, it's my local roads that are the problem.
S'nut