F41 Springs or Equivalent?

[kustomkyle]

I need new springs on the rear of my car (the fronts probably too). I was wondering where to get F41 springs or something just as good from the aftermarket as replacements. I want the same ride height, and I don't want something stiff. If possible, I'd like the lowest priced alternative if the OEM ones are pricey.

Also, does anyone know if the F41 front frame reinforcements make a difference as far as frame rigidity? I don't have intentions to make a drag car or anything (far from it).

 

[Vern]

Moog 5658 is a little stiffer than the factory f41 package springs. They are 1/4" shorter ride height and reasonably priced at most autoparts stores. The thicker front sway bar and the rear sway bar that come with that package help a lot! Also if find and get the sways bars (salvage yard or here or) get new poly end links and change them at the same time. The improvement will be dramatic and noticed the first time you hit a sharp cornering on/off ramp. If you add Edelbrock or Bilenstien shocks and some 15x7s with new 60 series tires you will almost think who traded your car in for BMW.

 

[kustomkyle]

Stiffer than F-41 springs? That doesn't sound good. How stiff are F-41's compared to the regular rear springs that have like 3 coils? If anything I'd want the suspension lifted a little rather than lowered. I guess 1/4" isn't much of a drop but?

 

[SBCregal]

if your springs are sagging and worn out, they could already be lower than stock ride height. installing new springs will probably raise the level of the car from where its sitting now (of course it all depends on how worn out the springs are)

 

[Truckedup]

I just installed the Moog 5658(S-10) front springs in my 81 El Camino.The stock springs appeared to be the regular stuff,not F-41.The front ride height is now about an inch higher than the old sacked out springs.I also did all the bushings,ball joints etc so maybe after a few hundred miles it will settle down a bit lower.Anyways,the front end is a lot siffer now.

 

[kustomkyle]

When you say stiffer, do you mean a rougher ride or do you mean the suspension is more responsive (not numb/floaty), or both?

I think I have a lead to some low-mileage used rear F-41's, maybe if that doesn't work out I'll look for them in the salvage yards, or possibly try to price the Moog ones at auto parts stores. How long do the F-41's last, effectively, mileage wise?

 

[Truckedup]

I haven't driven it yet,still finishing up engine work.But the hillbilly test of standing on the bumper and jumping up and down says it's a lot sitiffer than before.I put in urethane bushings so I'll have to drive it a bit to get "loosened up" for the real test.
Some say the F41 springs are too soft for serious road work.The S10 springs are shorter and supposedly they reduce the front end floating.There's also some theories on if it's better to run stiff springs and a moderate sized sway bar or softer springs and a thick sway bar.

 

[pontiacgp]

the moog 5658 spring rate is 579 lbs compared to the spring rate of 420 lbs which is the heavy duty spring used in a monte SS. The normal duty spring has a spring rate of 346 lbs. If your unsure what is meant by a spring rate is the pounds it takes to compress the spring 1 inch so 579 is considerably stiffer than the stock spring

for the back springs the stock normal duty has a spring rate of around 120 lbs (moog part # 5379) and the heavy duty is 142 lbs...(moog part # 5391)..

these springs, the front and back will be the stock ride height

 

[pontiacgp]

There's also some theories on if it's better to run stiff springs and a moderate sized sway bar or softer springs and a thick sway bar.

the reason for running a soft spring big bar setup is for circle track racing where you want the front to slam down with the shocks set up for a slow rebound so that the front end stays down through the corner...the theory being that the big bar adds to the spring rate when the car is corning helping the car to stay level but does not impede the nose from diving when braking and with the nose on the ground the car rotates better through the corner....... you might be surprised though because the soft spring set up we use is a higher spring rate than you use on the streets....

the stiff spring set up would shake your car apart....the front left springs we ran on one track was 1000 lbs....at other tracks the stiff springs are around 800 to 900..

 

[Vern]

The Moog 5658 will not give you a harsh ride just firmer and take out floatyness etc. Harshness often come from poly in the wrong places. Poly is good for motor mounts, end links, sway bar bushings, transmission mounts, but not in your A arm stuff or even control arms which its often used in with grease to help aleviate bind and squeaks.