tyler72

Hey guys,
I am going to have to upgrade my rear springs, the current ones are the originals and I think they are sagging. I am having tire rubbing issues, and compared to a lot of other 71-73 cars, mine seems to sit lower. I do not want a lowering spring, but possibly something a little stiffer. However, I do not want something too stiff, because I do drag race the car and right now the weight transfer on launch is really good. I am afraid if I go too stiff it will cause me to spin instead of hook up. So what are your opinions? Should I go with a 4 leaf, 4.5 leaf, or 5 leaf pack? Also, what are the real differences between them?

67mustang302

A lowering spring might raise your ride height, depending on how badly it's sagging.

kalli

i had the car a little low in back and when 2 girls in back the car was sitting on the rear tyres. and no. they were not fat :-)
so i replaced the springs with 5leaf. on hindsight 4.5 would have done for a bit more comfort, but i'm still happy
as shocks I have the gas-a-just but I'm going to kick them for a set of Konis (have konis in front) and the front stays steady while the back is jumping around.

I think must people will suggest 4.5 leafs for you for a good ride. but no idea what that does to drag racing.

urban_cowboy

My original springs were sagging a lot. I put in 4.5 mid eye springs and the car did lift, of course not as much as top eye springs. The 4.5 springs are a little stiff. I also have a rear sway bar and CE Slide-A-Link traction bars with add to the stiffness. With MT Sportsman S/R tires, I have very little tire spin with 500ft*lbs of torque on the street. I would think on the track, you would not have much problem with traction if you ran 4.5 springs. You will get less weight transfer than if you ran 4 springs, but you will not have any wheel hop issues, especially if you traction bars.

Deviousfred

5.5 HD M+ Springs FTW!

Just kidding. It would see to me that 4.5 springs would be good for what you need. However, I would take into consideration that even a mid-eye may raise your ride height like 67mustang302 said. Ask around and see if anyone has pictures of a car like yours with standard eye, and mid eye springs on their cars.

kalli

forgot to say. i bought mid-eye as well.

67mustang302

If you're more concerned about ride quality, you could go with 4's and then run CE Slide-A-Links. Just adjust them at the track for maximum launch control, and you'll still get the soft ride and the traction. Once I get around to it, I plan on doing a setup like Urban, 4.5's with the CE Slide-A-Links.

You could man up and convert to a 3 or 4 link though. But that's money and fabrication.

Norm Peterson

I'm not at all convinced that 4.5 springs will result in less "weight transfer".

It's only because they're stiffer that the rear of the car does not visibly squat as much on launch. But since it's not always easy to "see" what's going on inside the springs, it's pretty easy to conclude that less squat means less "weight transfer". It's also incorrect. "Weight transfer" causes squat, and squat is simply the visible evidence that weight transfer is happening. Not the other way around.


Norm

67mustang302

That's true. Look at 4 linked cars, when really set up right the rear wheels not only don't squat, but appear to move down and forward relative to the car. They have insane weight transfer, but they're also changing the instant center.

Deviousfred

Southside lift bars actually lift the rear end when you launch the car.