Rear sway bar suggestion

I'm looking to upgrade my front and rear sway bar. The front suspension will have stock style control arms with 1" lowering springs. The car is a 73 mach Q so what sway bar do I need for the rear? I was looking at the addco 3/4 but it says it's not a factory replacement bar. Suggestions on a sway bar kit that comes with everything I need that will work with 295's tires. Thanks

I'm looking to upgrade my front and rear sway bar. The front suspension will have stock style control arms with 1" lowering springs. The car is a 73 mach Q so what sway bar do I need for the rear? I was looking at the addco 3/4 but it says it's not a factory replacement bar. Suggestions on a sway bar kit that comes with everything I need that will work with 295's tires. Thanks

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What spring rate and shocks are you running?

I'm looking to upgrade my front and rear sway bar. The front suspension will have stock style control arms with 1" lowering springs. The car is a 73 mach Q so what sway bar do I need for the rear? I was looking at the addco 3/4 but it says it's not a factory replacement bar. Suggestions on a sway bar kit that comes with everything I need that will work with 295's tires. Thanks

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What spring rate and shocks are you running?

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I'm using factory spring rate from Eaton, Bilstein sport shocks and TPC 4.5 mid eye 1" lowering.

From "How to make your car handle"

The quoted section of the book was actually in caps...

"Here is the secret of chassis tuning: THE SUSPENSION WITH THE HIGHEST ROLL STIFFNESS WILL RECEIVE THE LARGEST PORTION OF WEIGHT TRANSFER CAUSED BY BODY ROLL."

Your front springs are most likely a little soft since they are stock spring rate in comparison to your rear leafs. My wild guess would be to run a large front bar and a small rear one. Maybe an 1 1/8" front and as small as you can find on the rear. This is just a guess...

Sway bars are inexpensive, it may be worth buying a few and swapping them out to see how it handles. If you go too big in the rear you will lift your inner rear tire during hard cornering in extreme cases, or at least loose enough grip that you will have tire spin.

From "How to make your car handle"

The quoted section of the book was actually in caps...

"Here is the secret of chassis tuning: THE SUSPENSION WITH THE HIGHEST ROLL STIFFNESS WILL RECEIVE THE LARGEST PORTION OF WEIGHT TRANSFER CAUSED BY BODY ROLL."

Your front springs are most likely a little soft since they are stock spring rate in comparison to your rear leafs. My wild guess would be to run a large front bar and a small rear one. Maybe an 1 1/8" front and as small as you can find on the rear. This is just a guess...

Sway bars are inexpensive, it may be worth buying a few and swapping them out to see how it handles. If you go too big in the rear you will lift your inner rear tire during hard cornering in extreme cases, or at least loose enough grip that you will have tire spin.

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How much difference would there be between Eatons factory spring rate vs their competition rate? With my sport shocks do I have to go with the stiffer spring or is it more of a suggestion? I think my factory spring rate with AC is 138ish.

Addco 550 front and 990 rear. 990 is a factory style bar but, you will need to source the rear bar frame mounts, bushings, and fasteners.

Chuck

Addco 550 front and 990 rear. 990 is a factory style bar but, you will need to source the rear bar frame mounts, bushings, and fasteners.

Chuck

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Exactly what I was looking for! Thanks

IMHO the 990 is a 7/8" bar and is too large for the rear if you have stock rate front springs. If you try it and find yourself not getting traction with your inside rear tire during auto cross events you might want to go down to the 3/4" 996... or smaller.

The 550 front is an 1 1/8" bar.

As for front spring rate, you would have to get ahold of Eaton to see exactly what your springs are. Since you allready have Bilstein sport shocks you probably don't use your ride to transport wedding cakes. You could try the 7/8" rear bar, take it to an auto cross and try it out. If you find yourself wanting more traction on your inside rear tire you could reduce the size of the rear swaybar, increase the size of the front or put higher spring rate springs in the front.

IMHO the 990 is a 7/8" bar and is too large for the rear if you have stock rate front springs. If you try it and find yourself not getting traction with your inside rear tire during auto cross events you might want to go down to the 3/4" 996... or smaller.

The 550 front is an 1 1/8" bar.

As for front spring rate, you would have to get ahold of Eaton to see exactly what your springs are. Since you allready have Bilstein sport shocks you probably don't use your ride to transport wedding cakes. You could try the 7/8" rear bar, take it to an auto cross and try it out. If you find yourself wanting more traction on your inside rear tire you could reduce the size of the rear swaybar, increase the size of the front or put higher spring rate springs in the front.

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I'm interested in a more firm ride but it won't be used for autocross. I'll give eaton a call. I fear that I'll need to sell the ones eaton made for me before even installing them....They are 1" lowering with the factor spring rate.

There are few choices for an OEM style/shaped/placed rear anti-roll bars. The ones I'm aware of are the factory .5 and .625 inch bars and the Addco bar. The are many more choices for non-OEM style bars that would likely work with the 295 rear tires but, may not accommodate tail pipes. If the intended use is auto cross or open track, then I would suggest adjustable bars both front and rear. This would permit tuning with changes in tires, springs, shocks, and other suspension components and geometry. Chuck

There are few choices for an OEM style/shaped/placed rear anti-roll bars. The ones I'm aware of are the factory .5 and .625 inch bars and the Addco bar. The are many more choices for non-OEM style bars that would likely work with the 295 rear tires but, may not accommodate tail pipes. If the intended use is auto cross or open track, then I would suggest adjustable bars both front and rear. This would permit tuning with changes in tires, springs, shocks, and other suspension components and geometry. Chuck

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The car will never see the track. It's strictly a cruiser, but I'd still like to firm up the factory suspension for spirited driving.

73' mach 1,

This is one book you need in your mustang library!

Mustang Performance and Handling Guide, 1964-1985 Paperback – September, 1985

by Pete Sessler (Author)

https://www.amazon.com/Mustang-Performance-Handling-Guide-1964-1985/dp/0879381973

It is recommend to have 1 inch in the front and 3/4 inch in the back.

The second book to have is

How to Make Your Car Handle Paperback – January 1, 1987

by Fred Puhn

https://www.amazon.com/How-Make-Your-Car-Handle/dp/0912656468

As you stated, it is recommended to get the OEM spring rate since that is what holds up the auto. We all know that the sway bars stops the body roll.

mustang7173

73' mach 1,

This is one book you need in your mustang library!

Mustang Performance and Handling Guide, 1964-1985 Paperback – September, 1985

by Pete Sessler (Author)

https://www.amazon.com/Mustang-Performance-Handling-Guide-1964-1985/dp/0879381973

It is recommend to have 1 inch in the front and 3/4 inch in the back.

The second book to have is

How to Make Your Car Handle Paperback – January 1, 1987

by Fred Puhn

https://www.amazon.com/How-Make-Your-Car-Handle/dp/0912656468

As you stated, it is recommended to get the OEM spring rate since that is what holds up the auto. We all know that the sway bars stops the body roll.

mustang7173

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Thanks for the links for the added information. I currently already have a set of Eaton springs with the factory specs. I had Eaton cut them for a 1" drop. It was after I purchased these that I was reading that maybe I got the wrong spring rate to match my shocks? I just want to make sure there is enough spring rate to not kill the shocks. In the end I just want to parts to match up nicely and not shatter my teeth if I hit a bump.

Now this is an interesting read. Good information is always appreciated.

In my case for my 71 Mach 1, when I purchased the Scott Drake front end kit, it came with a 1 1/8th anti-sway bar which I believe was an Addco. I purchased an Addco 7/8 OEM style from NPD as I was told that was the matching bar. My car rides on original springs, back and front with KYB gas-adjust shocks. It is an open dif as well.

Fitting the 7/8" bar was straight forward apart from needing to add a spacer behind the bolt that holds the fuel return line bracket to add more clearance.

I like to drive my car as hard as I dare around corners and so far I have not had any real issues with traction. What I did find interesting is that I may not need such a stiff rear a-s bar. I will be redoing my rear springs this winter with new bushings and maybe a half spring added to stop the right wheel hopping (4 speed car), so it may also be time to experiment a little with bar sizes. I must say, it was an amazing difference in cornering ability by adding the bigger front bar. Any more suggestions would be most welcome.

Geoff.

Addco 550 front and 990 rear. 990 is a factory style bar but, you will need to source the rear bar frame mounts, bushings, and fasteners.

Chuck

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Exactly what I was looking for! Thanks

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I posted this earlier but CJ Pony sells a Scott Drake 1 1/8 bar that is actually the addco 550. If you wait till it goes on sale it's usually $40 or so cheaper plus free shipping.

I also did the 990 bar. It comes with the bushings but you need to buy the plates that go on the springs. They sell them aftermarket really reasonable. I also needed to go to addco directly and get a new bushing set and mounting material that goes into the frame in the back. They advertising 990 Bar for a 7173 but they didn't line up. They were nice enough to send me the bushing and mounting brackets that go with the non-factory bar they sell that fit this correctly. If you buy the 990 kit and try to align the rear brackets up to the to factory holes that are already there you'll realize what I'm talking about. Just PM me if you need any more info.

Addco 550 front and 990 rear. 990 is a factory style bar but, you will need to source the rear bar frame mounts, bushings, and fasteners.

Chuck

Click to expand...

Exactly what I was looking for! Thanks

Click to expand...

I posted this earlier but CJ Pony sells a Scott Drake 1 1/8 bar that is actually the addco 550. If you wait till it goes on sale it's usually $40 or so cheaper plus free shipping.

I also did the 990 bar. It comes with the bushings but you need to buy the plates that go on the springs. They sell them aftermarket really reasonable. I also needed to go to addco directly and get a new bushing set and mounting material that goes into the frame in the back. They advertising 990 Bar for a 7173 but they didn't line up. They were nice enough to send me the bushing and mounting brackets that go with the non-factory bar they sell that fit this correctly. If you buy the 990 kit and try to align the rear brackets up to the to factory holes that are already there you'll realize what I'm talking about. Just PM me if you need any more info.

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Looking at the 2016 NPD catalog, they list 2 rear Addco bars for the 71-73, but 1 is not OEM style. Is this the one you bought? I got the OEM and it fitted perfectly with staggered shocks, other than I needed to move the fuel return line for more clearance. Also, does it make a difference with non-staggered shocks? The catalog does not fully describe this important detail. As I deal mainly with NPD, I don't know what other vendors are describing these products as.

I guess one needs to be sure what version you need and buy.

Exactly what I was looking for! Thanks

Click to expand...

I posted this earlier but CJ Pony sells a Scott Drake 1 1/8 bar that is actually the addco 550. If you wait till it goes on sale it's usually $40 or so cheaper plus free shipping.

I also did the 990 bar. It comes with the bushings but you need to buy the plates that go on the springs. They sell them aftermarket really reasonable. I also needed to go to addco directly and get a new bushing set and mounting material that goes into the frame in the back. They advertising 990 Bar for a 7173 but they didn't line up. They were nice enough to send me the bushing and mounting brackets that go with the non-factory bar they sell that fit this correctly. If you buy the 990 kit and try to align the rear brackets up to the to factory holes that are already there you'll realize what I'm talking about. Just PM me if you need any more info.

Click to expand...

Looking at the 2016 NPD catalog, they list 2 rear Addco bars for the 71-73, but 1 is not OEM style. Is this the one you bought? I got the OEM and it fitted perfectly with staggered shocks, other than I needed to move the fuel return line for more clearance. Also, does it make a difference with non-staggered shocks? The catalog does not fully describe this important detail. As I deal mainly with NPD, I don't know what other vendors are describing these products as.

I guess one needs to be sure what version you need and buy.

Click to expand...

for me I bought the OEM bar but the rear bushings metal didn't line up with the holes in had in the frame. I ended up having to longate the holes and used a ubolt through the the frame. I might have been sent the wrong bushings and bushing holders.

I posted this earlier but CJ Pony sells a Scott Drake 1 1/8 bar that is actually the addco 550. If you wait till it goes on sale it's usually $40 or so cheaper plus free shipping.

I also did the 990 bar. It comes with the bushings but you need to buy the plates that go on the springs. They sell them aftermarket really reasonable. I also needed to go to addco directly and get a new bushing set and mounting material that goes into the frame in the back. They advertising 990 Bar for a 7173 but they didn't line up. They were nice enough to send me the bushing and mounting brackets that go with the non-factory bar they sell that fit this correctly. If you buy the 990 kit and try to align the rear brackets up to the to factory holes that are already there you'll realize what I'm talking about. Just PM me if you need any more info.

Click to expand...

Looking at the 2016 NPD catalog, they list 2 rear Addco bars for the 71-73, but 1 is not OEM style. Is this the one you bought? I got the OEM and it fitted perfectly with staggered shocks, other than I needed to move the fuel return line for more clearance. Also, does it make a difference with non-staggered shocks? The catalog does not fully describe this important detail. As I deal mainly with NPD, I don't know what other vendors are describing these products as.

I guess one needs to be sure what version you need and buy.

Click to expand...

for me I bought the OEM bar but the rear bushings metal didn't line up with the holes in had in the frame. I ended up having to longate the holes and used a ubolt through the the frame. I might have been sent the wrong bushings and bushing holders.

Click to expand...

Jim, that's strange if you had to do mods to get it to fit. You did not say, unless I missed it, if you have comp suspension, staggered shocks. I'm assuming you do though. Also, did your car come with a factory rear a-s bar? That might explain the issue. Or perhaps you're right then that you did not get the proper install kit.

I am running 620# front coils and a set of 165# leaf springs from Maier Racing. I am using a 1 1/8" front and 7/8" rear sway bar. As for wheel size, I have 275/40-17's and there is a ton of room.