Looking to change to the lightest rate (60Nm ) front spring for my drag only car.

Do the spring rates affect static ride height?

 

Yes, they do, at least im quite sure. A change to a stiffer spring will mean a higher ride height, because the weight of the car doesnt compress it as much; of course, you only notice this change to a point, I guess about 650lbs/in or 112Nm/mm (on the other hand, a stiffer spring allows a lower ride height setting, since the car doesnt pitch around as much and contact the pavement as it would with a soft spring; dunno how exactly to explain, but its easy to get the picture).

A softer spring will mean a lower ride height. In your case it depends on how much weight you are running over the front axle. I see from your profile what engine youre running, so weight should be nearly identical. According to Corvette Specs, the Z51 front spring in 1987 was 66 Nm. Your front ride height should fall minimally. However, its probably a different matter if the 60Nm's youre thinking about are coil springs. In that case it greatly depends on the length of the spring.
Just the thoughts of an 17-year-old car-technician apprentice.

Youre probably best off asking some folks who have experience running drag-only C4s.

 

''if'' the springs had the same arch prior to installation, ride height would decrease with softer springs...but those sneaky devils in kentuck vary the unladen arch of the springs so that ''z'' height , when loaded with ''normal'' vette stuff & such upon installation, will be the same for all springs...you'll notice a definite dif in ''free end'' height from your shop floor to the spring when you have the front suspension apart and r&r the springs.

 

Thanks for info
Spring is for my '90 drag car currently has std 93Nm FHA spring.
Due to major diet front is way high so looking to return to level and gain benefit of softer spring to work with my "R series" QA1's adjustables

 

[QUOTE=rodj;1562090321Do the spring rates affect static ride height?[/QUOTE]

At the stock weight, they ride at the same height.

At a lighter-than-stock weight, the softer springs will ride a bit higher than the Z07/Z51 springs.

At a heavier-than-stock weight, the softer springs will ride a bit lower.

Since you are lighter than stock, the stiffer spring would drop your ride height a bit, but isn't going to help weight transfer for the launch.

 

reducing weight front or rear will increase ride height respectively for all rate springs, but the softer springs will rise a bit more than the higher rate will for the same weight reductions.
lowering the front with full oem load can be done by ''shaving'' rubber from the outer pads on the spring (do not take all the rubber off) and ''drop'' will be abt 2.5x rubber removal on 84-87 and abt 4x rubber removal on 88+... or by cutting down the inner spring mount pads and using substitute plastic or rubber ''fulcrums'' at those points, but drop will only equal height of removed material 1:1, and contact of the top of the spring with the frame above, in the center of the spring, may occur with damage to the spring (a gob of grease on top of the spring helps UNLESS you are in a dusty environment where the grease will hold grit and be even more aggresive than dry contact)
if you've really got your nose in the air a huge distance, cutting the oem outer spring mounts out of the lower a-frame and fabricating new spring mounts that bolt on (don't weld unless you can properly re-temper the alum a-frame) and are lower will endanger all the snakes--adequate ground clearance under the ''lowered'' spring support and protection of the spring from road debris may be issues...might be simpler to pay the price of a few extra pounds and use coil-over springs, tie-wrap everything together to keep the bits honest when you jump out of the hole (start)

 

"might be simpler to pay the price of a few extra pounds and use coil-over springs"

That is the ultimate aim; $$$ not weight not a factor at present as I have gutted everything forward of the firewall so can afford to add some back in.
Short term was looking to see what I could achieve with a lighter spring.Rear is raised on QA1 coilovers (9" / 4 link ) to clear 28" slicks but still nose high at rest.
Prob good for start line but not very aerodynamic at speed.