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For a GM "A" body with a big block Olds. These springs are supposed to lower it 1" and have a 530 Lbs linear rate. Anyone use them on a 1970-72 big block Olds? If so, did they lower 1" and how was the ride height?
The spring rate varied depending upon the vehicle configuration, such as AC, non-AC, HD suspension, FE2, etc. I think the ride height was lower for the 442 vs the "other" Cutlass models, too.
Here's info I have from the old online Moog catalog:
I have UMI drop springs front and rear on my 71. I initially started with their 2" lowering springs, but they lowered the car way too much. UMI replaced them with some 1" lowering springs which sat 2" higher than the 2" lowering springs. This is on my 71 with an iron block LS engine. I personally think another 1/2" down would be perfect but i'm not cutting springs so this will do. The ride is nice, spring rates are slightly stiffer than stock, but dont ride like a shopping cart.
For a little better reference, my wheels are 18x8 in the front, with 245/45R18 tires which are 25 7/8 tall with weight on them. Wheel lip sits almost right at 26". Frame behind the front wheel sits at 8 1/4" and the rear bottom of the fender is just a hair under 10". This is with the UMI 1" drop springs.
I also bought the UMI 1" drop springs but haven't put them on the car. Was debating if I should return them and get the 2" drop springs, but now I'm not so sure. Ach, did you buy UMI'S shocks too?
I am still running some old Monroe shocks right now. I have gone back and forth on which shocks to get. I initially looked at the old go-to Bilsteins, then the Varishock SS, but havent been able to find any real world reviews. UMI's shocks were next on the list and will probably end up being the ones I go with. I dont need an adjustable shock for how the car is used.
With the 2" lowering my tires rubbed when taking any significant turn. Their 2" lowering springs are more like 3" lowering springs. I still have them sitting in my garage, i dont know how bad they would be to ship but if you want them I would let you have them for the cost of shipping.
I bought UMI 1 inch lowering springs but contemplated returning them for the 2 inch lowering springs. If you say they lower the car that much, I'll just stick with the 1 inch lowering springs. Thank you for the offer though.
With the 2" lowering my tires rubbed when taking any significant turn. Their 2" lowering springs are more like 3" lowering springs. I still have them sitting in my garage, i dont know how bad they would be to ship but if you want them I would let you have them for the cost of shipping.
For a little better reference, my wheels are 18x8 in the front, with 245/45R18 tires which are 25 7/8 tall with weight on them. Wheel lip sits almost right at 26". Frame behind the front wheel sits at 8 1/4" and the rear bottom of the fender is just a hair under 10". This is with the UMI 1" drop springs.
I'm guessing you meant 245/40/18 for the fronts since 245/45/18s are 26.7" tall. Sorry random I know but I'm running the 245/45/18s so very familiar with the height. Also that's a short front tire be running for street driving/ground clearance especially if you're running headers even with only the 1" drop springs.
The Doug's headers I have on the car sit very tight to the floorpan. They connect to the rest of my exhaust with v-band clamps, with the clamps being the lowest part sitting 6" from the ground. They sit about 1/4" below my transmission pan. I haven't had any issues with speed bumps yet. The Nitto 555G2's may be different sized, but I am looking at them now and they are 245/45ZR18. I am only running 35psi on them, so the squat must account for the difference between my measurement and the tech data of 26.7"
Last edited by ach1992880; May 11, 2020 at 01:28 PM.
Gotcha - that makes total sense. I didn't even think about what the measurement is of a tire with the car's weight on it is vs. the rim/tire measurement not mounted on the car. I was thinking you just had a typo with a 245/40/18 = 25.7" vs a 245/45/18 = 26.7" but as you pointed out those are "before mounted' heights. As mentioned I'm running the same size 245/45/18 front tire on my 442 - also on an 18x8. My front tire is a Michelin Pilot 4S:
I'm trying to upgrade to a much wider front rim and tire but that's another story as being described in my cars updates here under the Major Builds and projects section.
