Front spring assistance needed

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RIBS

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Hi all, I am rebuilding my front end, and have new springs to install. The old springs appear to have about eight windings and the new springs appear to have nine windings. Anybody here have measurements or additional information? The new springs are Elgin brand specifically sized to the body style, year and options for the car. The car had a great ride high before I disassembled it, I don’t want this to send my front end way up. I’m wondering if the previous owner had the springs cut.
The old spring is 16 inches uncompressed and the new spring is 17 inches uncompressed.
1971 Mustang convertible, 302 auto C 4, Air, PS, PB.
 

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Joined
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1971 Mustang Mach 1, M code, 4 speed.
Hi all, I am rebuilding my front end, and have new springs to install. The old springs appear to have about eight windings and the new springs appear to have nine windings. Anybody here have measurements or additional information? The new springs are Elgin brand specifically sized to the body style, year and options for the car. The car had a great ride high before I disassembled it, I don’t want this to send my front end way up. I’m wondering if the previous owner had the springs cut.
The old spring is 16 inches uncompressed and the new spring is 17 inches uncompressed.
1971 Mustang convertible, 302 auto C 4, Air, PS, PB.
Send 'em back and buy from EATON Detroit Springs and get the CORRECT springs for your car. You can order directly or from NPD. Eaton make 1" lowering if you want that option.
Back around 2014, I bought a "front end kit" (Scott Drake crap) and the springs that came with it were 2"longer and the mechanic had one hell of a job putting them in. The front end sat 2" higher and looked like crap. So, I reinstalled the original springs that were still good and to spec. I was able to return the springs after I convinced the dealer they were totally wrong.
 

RIBS

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Send 'em back and buy from EATON Detroit Springs and get the CORRECT springs for your car. You can order directly or from NPD. Eaton make 1" lowering if you want that option.
Back around 2014, I bought a "front end kit" (Scott Drake crap) and the springs that came with it were 2"longer and the mechanic had one hell of a job putting them in. The front end sat 2" higher and looked like crap. So, I reinstalled the original springs that were still good and to spec. I was able to return the springs after I convinced the dealer they were totally wrong.
FYI, I am 90% certain these came from NPD. Anyhow they are from a well known spring supplier, and sized properly for the car and options…l
 
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1971 Mustang Mach 1 M code 351 4 speed
Is the part number on the box 8356? That is the Elgin spring part number I got for my 71 Mach 1 from NPD, that spring is identical to the Moog 8356. Elgin lists 4 different spring numbers for the 1971 Mustang convertible with the 302. My car sits high in the front with the Elgin springs, but it has almost not been driven, so I expect it to sit lower after some driving, but it will still be high. One thing that I found out is that according to Elgin and Eaton Detroit, Ford used the same spring in the 1971 Mach 1 with either the 302, 351 or the 429, which makes no sense to me. If both the companies are correct, then the 351 and 302 cars had to sit high, or the 429 were very low. No cars from the Muscle Car era were ever low from Detroit in the 60's and 70's, they all sat high.

Here is the Elgin catalog, look at page 134:


Here is the Eaton catalog, look about 1/4 page down to do a search:


Eaton lists the MC1278 coil spring fitting:
1- 1971 Mustang Mach 1 351 WITHOUT A/C
2- 1971 Mustang Mach 1 429 WITH A/C
3- 1971 Mustang Mach 1 302 WITH A/C
4-1971 Mustang convertible 302 WITH A/C improved handling (ie: HD suspension)

None of this makes sense, and if you have a 429 with A/C and a 351 without, there has to be a significant height difference, same with the 302 and A/C.
 

RIBS

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1971 Grabber Blue 302 C4 Convertible
Is the part number on the box 8356? That is the Elgin spring part number I got for my 71 Mach 1 from NPD, that spring is identical to the Moog 8356. Elgin lists 4 different spring numbers for the 1971 Mustang convertible with the 302. My car sits high in the front with the Elgin springs, but it has almost not been driven, so I expect it to sit lower after some driving, but it will still be high. One thing that I found out is that according to Elgin and Eaton Detroit, Ford used the same spring in the 1971 Mach 1 with either the 302, 351 or the 429, which makes no sense to me. If both the companies are correct, then the 351 and 302 cars had to sit high, or the 429 were very low. No cars from the Muscle Car era were ever low from Detroit in the 60's and 70's, they all sat high.

Here is the Elgin catalog, look at page 134:


Here is the Eaton catalog, look about 1/4 page down to do a search:


Eaton lists the MC1278 coil spring fitting:
1- 1971 Mustang Mach 1 351 WITHOUT A/C
2- 1971 Mustang Mach 1 429 WITH A/C
3- 1971 Mustang Mach 1 302 WITH A/C
4-1971 Mustang convertible 302 WITH A/C improved handling (ie: HD suspension)

None of this makes sense, and if you have a 429 with A/C and a 351 without, there has to be a significant height difference, same with the 302 and A/C.
I have the Elgin 8330, which is correct for my car, 71 convertible, 302, automatic, AC. It’s just not a match for what I pulled out, which is a 50 year old car, which I have owned 6 months. Who knows if it’s original springs….
 

c9zx

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These cars were front high from the factory, I've owned 5. If you don't like that look you will need a lowering spring or cut the springs. Eaton is the only source for correct springs. The other springs result in making the mustang look like off road 4 wheel drive vehicle. Chuck
 

Hemikiller

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I figured out a long time ago to not trust aftermarket suppliers to have the correct application data. Problem is that many applications have been consolidated over the years, there's just no reason for them to carry exact springs for these cars, there are just not enough sales to justify the expense. Ford had dozens of spring part numbers for the 71s, depending upon body, engine, trans, PS & AC option mix, build date, etc.

before 11/9/70
4U - C7ZZ-5310-AK ----> load: 1720, 9 1/2 coils, .600" wire diameter, 16 5/8" length
after 11/9/70
4E - C7ZZ-5310-B ----> load: 1650, 9 coils, .600" wire diameter, 16 3/8" length

The build date change was simply Ford figuring out that the PS option on these cars was not a big enough change in the load to warrant a fourth spring option.

The 8330 spring specs are - load: 1800, .625" wire diameter, 16 5/8" length

This is what most companies consider "close enough". If you're running a bunch of aluminum parts on the engine, you'll probably need to trim the coils to get it to an acceptable ride height.



71_standard_spring.jpg
 
Joined
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My Car
1971 Mustang Mach 1, M code, 4 speed.
Is the part number on the box 8356? That is the Elgin spring part number I got for my 71 Mach 1 from NPD, that spring is identical to the Moog 8356. Elgin lists 4 different spring numbers for the 1971 Mustang convertible with the 302. My car sits high in the front with the Elgin springs, but it has almost not been driven, so I expect it to sit lower after some driving, but it will still be high. One thing that I found out is that according to Elgin and Eaton Detroit, Ford used the same spring in the 1971 Mach 1 with either the 302, 351 or the 429, which makes no sense to me. If both the companies are correct, then the 351 and 302 cars had to sit high, or the 429 were very low. No cars from the Muscle Car era were ever low from Detroit in the 60's and 70's, they all sat high.

Here is the Elgin catalog, look at page 134:


Here is the Eaton catalog, look about 1/4 page down to do a search:


Eaton lists the MC1278 coil spring fitting:
1- 1971 Mustang Mach 1 351 WITHOUT A/C
2- 1971 Mustang Mach 1 429 WITH A/C
3- 1971 Mustang Mach 1 302 WITH A/C
4-1971 Mustang convertible 302 WITH A/C improved handling (ie: HD suspension)

None of this makes sense, and if you have a 429 with A/C and a 351 without, there has to be a significant height difference, same with the 302 and A/C.
Ok, not to create a shit storm, but your listing is incorrect for the 429. MC 1278 standard ride height is WITHOUT AC. AC weighs quite a lot. MC 1278 does list for the 302 vert WITH AC and the 351 2v & 4V WITHOUT AC. It is confusing for sure and I'm with you on that.
Don't forget, Eaton make their springs from SAE 5160 high alloy spring steel and made to Ford's original prints and spec. Other manufactures don't (always) list the steel they use and THAT makes a huge difference to quality.
I can't remember for sure now where I got the unloaded specs for my 71 Mach 1. I may have been in direct contact with Eaton. I do know that the correct unloaded height for these is 15" and would probably be MC1278. These are the springs I reinstalled. I seem to have lost the spec diameter of the wire, so I can't quote that right now. Wire diameter and number of coils combine to the spring rate required for a given vehicle.
Some time ago, I posted a video on Eaton Springs springs. I'm not going to link it here right now, but it was very informative. I was going through a saga with my rear leaf springs, having bought a set of Grab-A-Track 4 1/2 leaf that eventually started to bend backwards. In my research, I found that many of the so-called correct fit springs for our cars, were made from 4140 tool steel (and made off-shore), not proper spring steel. Non of the manufacturers listed their steel as 5160 or the equivalent.
Bottom line here was for me, buying cheaper spring that I thought would be good, ended up costing me more than double. That goes for back and front springs.
 

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piper62j

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I've always used Moog when available.. Never had performance issues.. Eaton is excellent, but I found their prices to be a bit high.. Best to shop around for the quality and price that fits your project.
 

RIBS

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1971 Grabber Blue 302 C4 Convertible
I figured out a long time ago to not trust aftermarket suppliers to have the correct application data. Problem is that many applications have been consolidated over the years, there's just no reason for them to carry exact springs for these cars, there are just not enough sales to justify the expense. Ford had dozens of spring part numbers for the 71s, depending upon body, engine, trans, PS & AC option mix, build date, etc.

before 11/9/70
4U - C7ZZ-5310-AK ----> load: 1720, 9 1/2 coils, .600" wire diameter, 16 5/8" length
after 11/9/70
4E - C7ZZ-5310-B ----> load: 1650, 9 coils, .600" wire diameter, 16 3/8" length

The build date change was simply Ford figuring out that the PS option on these cars was not a big enough change in the load to warrant a fourth spring option.

The 8330 spring specs are - load: 1800, .625" wire diameter, 16 5/8" length

This is what most companies consider "close enough". If you're running a bunch of aluminum parts on the engine, you'll probably need to trim the coils to get it to an acceptable ride height.



View attachment 59244
Thanks. I guess I will put it together and get All the parts bolted on and see where it sits, and go from there….mine is a 302 C4 auto AC PS PB convertible built 12/4/70. Right now it has no fenders, hood bumpers interior top, or lights, just a driver seat and running shell, so I probably need to add all the widget back to it….also the condensor and compressor are out of it and they might not go back in depending on wife’s budget answer….LOL. so I might end up pulling springs in a year and cutting an inch off.
 
Joined
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I've always used Moog when available.. Never had performance issues.. Eaton is excellent, but I found their prices to be a bit high.. Best to shop around for the quality and price that fits your project.
Agreed, Eaton prices are a bit higher than most aftermarket, but, as the old saying goes, you get what you pay for. Your life may depend on what you put in your car. Somethings you don't cut corners on as far as I'm concerned. That of course is just my opinion, to each their own.
 
Joined
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1971 Mustang Mach 1 M code 351 4 speed
Ok, not to create a shit storm, but your listing is incorrect for the 429. MC 1278 standard ride height is WITHOUT AC. AC weighs quite a lot. MC 1278 does list for the 302 vert WITH AC and the 351 2v & 4V WITHOUT AC. It is confusing for sure and I'm with you on that.
Don't forget, Eaton make their springs from SAE 5160 high alloy spring steel and made to Ford's original prints and spec. Other manufactures don't (always) list the steel they use and THAT makes a huge difference to quality.
I can't remember for sure now where I got the unloaded specs for my 71 Mach 1. I may have been in direct contact with Eaton. I do know that the correct unloaded height for these is 15" and would probably be MC1278. These are the springs I reinstalled. I seem to have lost the spec diameter of the wire, so I can't quote that right now. Wire diameter and number of coils combine to the spring rate required for a given vehicle.
Some time ago, I posted a video on Eaton Springs springs. I'm not going to link it here right now, but it was very informative. I was going through a saga with my rear leaf springs, having bought a set of Grab-A-Track 4 1/2 leaf that eventually started to bend backwards. In my research, I found that many of the so-called correct fit springs for our cars, were made from 4140 tool steel (and made off-shore), not proper spring steel. Non of the manufacturers listed their steel as 5160 or the equivalent.
Bottom line here was for me, buying cheaper spring that I thought would be good, ended up costing me more than double. That goes for back and front springs.
I am glad that you think that the MC1278 is for a 429 WITHOUT A/C, but that is not what Eaton Detroit lists. They list it for 429 WITH A/C:
 
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1971 Mustang Mach 1, M code, 4 speed.
I am glad that you think that the MC1278 is for a 429 WITHOUT A/C, but that is not what Eaton Detroit lists. They list it for 429 WITH A/C:
Ah! I see the confusion and YES it does say for the Mach 1 or Fastback 429, WITH A/C, but NOT the convertible where it say WITHOUT A/C. How confusing can you get eh!!!! I hope that settles that score.
 
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