[Nubs69]

I installed replacement coils over the winter. I have a 454 in the car and purchase Eaton springs from NPD. The NPD part number is C-7412-50. It is listed as the correct spring for a Big Block 1968. The car has been sitting on the wheels with the engine in for 5 months. So the springs should be settled. She is sitting about 1-1.5 inches high in the front. I want to trim the front coils. Is there a rule of thumb for triming? 1/2 coil equals 1 inch??? or so. If not...how much should I trim off and then reinstall for a test fit? 1/2 coil....1/4 coil??? Any thoughts?

Thanks,

[pdq67]

See if you can still return them and then buy the chea-, er, eh, "inexpensive" roundy-round car coil spring adjustable cans from like Speedway Motors and whatever pound rate cheap short coil springs you want to try.

Wished I had!!!!!!!!

pdq67

[68 Ragtop]

Originally Posted by Nubs69

I installed replacement coils over the winter. I have a 454 in the car and purchase Eaton springs from NPD. The NPD part number is C-7412-50. It is listed as the correct spring for a Big Block 1968. The car has been sitting on the wheels with the engine in for 5 months. So the springs should be settled. She is sitting about 1-1.5 inches high in the front. I want to trim the front coils. Is there a rule of thumb for triming? 1/2 coil equals 1 inch??? or so. If not...how much should I trim off and then reinstall for a test fit? 1/2 coil....1/4 coil??? Any thoughts?

Thanks,

Before trimming, make sure the top of the spring is correctly located in the pocket.
If it is out, it can cause the front to sit 1-1.5" too high.
There is an inspection hole to check, but it's a little difficult to see.

[fletchj3]

If it is not seated correct, how do you seat it?

[Everett#2390]

Remove the tension from the spring and set the flat end of the coil into the seat in the frame.

There is an inspection hole in the subframe, approx 3/8 inch diameter, to view the end of the coil, regardless of where the bottom end of coil sets in the lower control arm.

[Nubs69]

Thanks for the info. I will check so see if she is seated correctly and report back.

[EatonDetroitSpring]

As PP said, do check to make sure the springs are seated properly. But also, how far together is the car? I see the engine is in. What about the rest - Interior, Glass, Trans, etc.? These items do have a great effect on the weight, and that effects how she sits. Check out our website, we have several posted Tech Questions on this subject, or feel free to contact us.

[Everett#2390]

Welcome to the Club, Eaton Springs.

[Miikeremains]

I cut 1/2 coil off my hotchkis springs and it lowered about 1 inch if that's any help to ya.. Although I suppose this should not be considered a rule of thumb since springs have diff pressure ratings.. I would never cut more than 1/4 coil at a time.. There's no going back once they r cut...

[EatonDetroitSpring]

NPD part number C-7412-50 is the right spring for the both the coupe and convertible '68. So let's see if we can find out what is wrong before cutting coils. 1st question, is the car complete? Remember, springs support weight and if the car is not complete the springs are not at their designed load. While we are talking about weight, has she been modified in ANY WAY????? All those "special" things done result in a change of sprung weight. Taking things off, using alumnium intakes or manafolds or heads lighten the front a whole bunch. In fact the mentioned items lower the weight of a big block to the weight of a small block. Lighter engine means different springs.
Second thing, have you driven the car? Once new springs have been installed they have to be worked. Driving is the best way of working them. Jumping on the bumper doesn't get it. Take her out and drive her like you stole it. Hit bumps, brake hard, hit the gas, make those springs move up and down.
Once she is back in the garage let's check the ride height. All the the following heights are if the car has F70 x 14 tires, so adjust if you have different tires.
With the car on level ground measure back 33-inches from the center of the front tire, then measure from the ground to the bottom of the rocker panel, stock is roughly 9-3/8 inches.
On the rear measure 20-inches forward of the centerline of the rear tire, then measure from the ground up to the bottom of the rocker panel, stock is roughly 8-5/8 inches.
If all else fails, call me - Mike Eaton 313-963-3839.

[1stGenLvr]

I never buy a spring listed for a big block for the exact reason you state. Every one I have seen will raise the car up, some even more than your springs. I always buy SB, no air etc factory replacement and have been satisfied with the correct (more or less) ride height.

[Nubs69]

Mike,
The car is completely assembled. I drove her around the neighborhood and breifly on the street to test everything out. I used your measurments and she is close to your stock measurements but still to tall for my liking. I ended up triming 3/4 of a coil off the bottom of the springs and if what you say is true about settleing after driving.....She will be perfect. Thanks for the information.

Matt

[EatonDetroitSpring]

Matt,
Glad to hear she is siting how you want her to. Funny thing about ride heights and new springs. Our springs are designed to sit the vehicle at the factory height specs, unless we are told otherwise. That being said, people in general have come to relate “stock ride height” of any particular vehicle with the way they see them sitting now and not how they sat from the factory. That’s why new correct springs sometimes seem to make a car sit different than what we are used to seeing.
If all the cars you’ve ever seen were 2” lowered, or 1" higher, your brain would say that was stock.
Bottom line is we are glad the car is now to your liking. - Mike