Looking at updating the front suspension this fall/winter on my '66 Skylark 4-door hardtop. QA1 offers 10" free length springs in a variety of spring rates for coilover setups and from what I can calculate based on weight the spring rate should be around 400 but wanted to see if anyone has any opinions or experience with different spring rates. Will be going to tubular upper and lower, adj. coilovers, new spindles (stock heigh or 2" drop haven't decided), 11" disc brakes, new master/booster, replacing body mounts, and if the budget comes out well I may start on the rear suspension, too. Thanks! -Steve
I take it you got your 400# recommendation from QA1's web page? https://www.qa1.net/tech-center/tec...ring-rate-for-qa1-direct-fit-pro-coil-systems Their baseline for an A-body @1850 lbs in the front is the 400# spring. There is another chart which will adjust the spring depending on engine and accessories such as air conditioning. You can adjust further for the road conditions and driving style you prefer.... if you drive primarily on smooth roads and want to optimize hard cornering, go stiffer. If you drive on pothole filled roads or want to optimize weight transfer for drag racing, go softer.
Yup, I used their spring charts and assumed about 1875 lbs on the fairly high end with the 300 c.i. engine. Not really looking to make a barn burner for cutting corners and definitely not drag racing with it. It's just destined to be a cruiser but would like to get a little more stability. Planning to try to do a Hot Rod Tour or follow a drag and drive event next year. Thanks for your input, Walt. Much appreciated.
For what it's worth, the stock spring for a '66 GS is rated at 370 lbs/in. The plain Skylarks are about 300#. Even the 66-67 GTO's used a soft-ish spring, 314#. I put the 5244 GTO spring (314#) in my GS years ago (before I knew better), they do feel soft with the 401, it bottoms out too easy. In my 66 Special w/ 300, I put some old sagging GS springs in (370#). I like those for ride height (near stock) and ride. I can't say for sure if the stock coil vs the QA-1 coilover rates can be directly compared. The geometry is about the same,so I would guess yes. 350-400# would be your range. If your ride height will be lower than stock, higher rates would make it less likely to bottom out. Give QA-1's tech support a call and see what they say.
