Vintage Mustang Forums banner
  • Hey everyone! Enter your ride HERE to be a part JUNE's Ride of the Month Challenge!
  • May's Ride of the Month contest ended with a tie! Go to this thread to vote on the winner! VOTE HERE
1 - 20 of 28 Posts

·
Premium Member
Joined
·
6,415 Posts
Discussion Starter · #1 ·
The rear suspension in my car is to stiff. When I was screwing it back together ten years ago, I bought the "Really Big Suspension Kit" (?) from Canadian Mustang.

Well it's true that you get what you pay for and now I need a change. The car rides like a stone wagon. It has 5-leaf mid-eye springs and KYB Gas-a-Just shocks out back.

What are you guys running and what would you recomend?

Who makes the best? What material (composite)? Single or multiple leaf?

Please don't say to swap it out for a 3 or 4 link or independant rear, as the money isn't there for that. Just looking for a decent handling and riding rear leaf setup.

Thanks.
 

·
Registered
Joined
·
1,435 Posts
I've got 165# 4-leaf standard eye springs with poly bushings from Mustangs Plus, Konis set about half-way between soft and firm, and a 7/8" rear anti-roll bar. The ride is acceptable, and I can autocross without embarassment.
 

·
Registered
Joined
·
15 Posts
I'm surprised. I run 5 leaf from Mustang Plus and they don't feel that stiff. I do run Spax adjustible rear shocks. The ride is not harsh at all...???
 

·
Registered
Joined
·
1,446 Posts
I have Maier 4.5 mid eye leafs with Koni classics. It's definitely firm, but I wouldn't say harsh.

Maybe try changing shocks first. I've heard from more than one person who say the KYB shocks are stiff.
 

·
Registered
Joined
·
218 Posts
call Bill Maier at Maier Racing... he loves to talk suspension. In my 66 vert I have his 165 Racing spring, poly bushings with Edelbrock IAS shocks. Even with traction masters hooked up (which he has convinced me to take off) I think the ride is very compliant and not at all harsh... a nice comfortable firm ride (I also have TCP coilover in front set in the middle on both settings).
 

·
Registered
Joined
·
2,061 Posts
I've been very happy with my 200# Flex-a-form composite springs and GR-2 shocks. I wish I had gotten the 2" drop ones now to match the front (~1 1/2" drop from stock), but the ride is amazing. The recovery is very quick and the rear is very tight going around corners. The springs also feel closer to 140-160# 4 leaf steel ones in ride quality--firm and controlled, but not stiff. The car doesn't move up and down much over bumps, either, just the wheels do. I just wished they weren't quite so expensive, but as you said, "you get what you pay for."
Daniel
 

·
Registered
Joined
·
1,334 Posts
I'm a big proponent of a lightly sprung rear, after all the back end of an early model is very light. I want the suspension to actually respond to changes in the pavement, not just skip across them.

I've got the Grab-A-Trak performance 4 leaf mid eyes rear leafs with a panhard bar, traction masters and Edelbrock IAS shocks. This along with the subframe connectors makes the rear end firm but not overly stiff. I plan to upgrade my traction masters by swapping out the fixed bar with some Afco spring rods, per Cobra Automotive.

The two most noticable changes I made to the rear were:
Removing the rear sway bar and installing the subframe connectors and panhard bar. This change made the rear end much more predicable.
Swapping the rear KYB shocks out for the Edelbrock IAS shocks. The KYB's didn't let the leafs respond. If I was cornering and hit a pavment change the rear would bounce or skip out with the KYB's - The Edelbrocks allow the leafs to react and keep the tires in better contact.

Tim
 

·
Registered
Joined
·
7,032 Posts
Mark,
I have the same rear springs, with 720 fronts and Koni's. I also agree, it's too stiff. If you want handling, I'd contact Maier Racing. That's where I'm going to buy my next springs.
 

·
Registered
Joined
·
1,218 Posts
Find a local spring shop that will work with you to get the ride height and stiffness you want.

Also, I am convinced that no small block car can be anything but harsh with KYB Gas-A-Justs. Before you change out the springs, try a road test on a bumpy road with no shocks at all in the rear. If ride quality is acceptable, then you know the shocks are the problem.

As far as a replacement shock, Bilsteins from Maier Racing are the way to go.
 

·
Registered
Joined
·
2,061 Posts
68fastwilliams said:
Yea, the shocks are a problem.

Daniel,

If you don't mind what did you have to give for those springs? How much do they weigh?

Thanks
I paid $435 shipped for the springs, not too bad for the weight savings. 40 year old stock 4 leaf springs were 33lbs each, new FAF springs were 8 lbs each, so 16lbs for the new pair compared to 66lbs a pair for the old. This is a bit misleading, since the FAF springs I got are actually comparable in rate to the 5 leaf steel springs which would add ~5-8lbs each side. The ride, though is much better than with the steel springs since you are not trying to lift and lower 25-30 more pounds up over each bump/dip and since you have no interleaf friction and variable rates as each leaf wraps up. I haven't noticed any tendency to oversteer since I lightened the rear so much, but I still plan a battery relocation to offset the F/R weight ratio.

I'm using poly bushings (FAF-supplied for front and rear) with poly racing shackle bushings up top for the shackle to frame. I did reverse the eyes for a ~1" drop from stock, but would like to have another half inch or so drop for dialing in the rear.

Daniel
 

·
Registered
Joined
·
663 Posts
I've got 5 1/2 leaf springs with a mid eye from Mustangs Plus with poly shackles and I like em. Be sure to take into consideration that different people have different taste. What may be too harsh for someone may be good for you.
 

·
Registered
Joined
·
8,413 Posts
68fastwilliams said:
Thanks Daniel!
When I was out in Bend 2 months ago I rode in Daniel's car with the new FaF springs. It was a more forgiving and comfortable ride then my 66 with 4 1/2 leaf mid eyes!

I just need to justify the expense now ;)
 
1 - 20 of 28 Posts
Top