I have the 17" Year One rims with 255/50R17 tires. Front measurement(1" back from the door) is 12.25" and the rear(3" forward from the wheel housing) is 12.5". Can someone please suggest what springs I need to lower it to stock ride height? A friend suggested to use coil overs to lower it but I think I would prefer to replace the springs. Thanks in advance.

 

27.1 inch diameter tires and that much space above tire to fender lip... wow.

Your tires are 1 inch taller than stock, and the gap is still huge.

Factory correct for your car is 26.1 inch diameter. F78 14 = 205 75 14

I'm assuming your measurements are emulating the factory's rocker panel measurement height points? Page #5 of the AMA here https://over-drive-magazine.com/wp-c...Specs-1-40.pdf If thats the case your car is sitting 3 inches higher than factory...



Why not just order factory correct springs from Summit Racing or the like... https://www.summitracing.com/parts/u...lass/year/1972 But I would confirm with them as to exactly what you want to acomplish. They are very helpful.

At the same time I see the low hanging header collectors so proceed with caution. I had a serious bottoming out issue with my then 67 Cutlass Coupe and the header collector flanges, and my ride was considerably above stock height. Headers are a pain in the ***.

 

Tom

Please measure your Supremes lowest point in relation to ground clearance. (which is likely the collector flange)

And keep in mind Supremes were lowered during the original muscle era.

1967 5.5 inches at lowest point.
1970 4.5 inches ...
1972 4.7 inches ...

And all those measurements are unladen weight.

Now sure a firmer suspension will help, but ...

Here is a 2018 M3 just trying to navigate his own driveway on a daily basis. Thanks to heyyouduh of the bimmerpost.com.


https://f80.bimmerpost.com/forums/sh....php?t=1842791 Post #1.

And yes you can try to angle in, approach slower, etc. But if you ever slip and enter haphazardly at speed, forget it. heyyouduh's exhaust is what is making contact, coincidentally. And his BMWs lowest point of ground clearance happens to also be 4.7 inches just like your 72.

Now imagine speed bumps, dips on the highway, curb cut outs with high lift, etc. You may have to keep your Olds as high as it sits, to not have issue as presently constituted.

P.S. apples to oranges, fine, but my lifted 67 with tall tires and headers still shared all the same issues...

 

I don't know if this will help but I use Moog 6435 rear springs and stock height fronts in my '72 - Moog no longer makes the rears but Mevotech does under their p/n SMS6435. I run 17x8 Torq Thrusts all around on 245-50-17 tires - 6435 specs:

Bar Diameter - Inches 0.56 Bar Diameter - MM 14.30 End Type 1 Pigtail End Type 2 Pigtail Feature 1 Powder-coated to protect against corrosion Feature 2 Designed to lower stresses for longer service life Feature 3 All coil springs are 100% load tested