Gen1 Watts Link input for a ‘66 coupe

[BoulevardofRustedDreams]

I’m starting restoration of my ‘66 coupe which will be largely a group 2 inspired build. I want to autocross the car and do some more local SCCA type events. I want to address the rear end/suspension first. The car has a 8” under it which I’m most likely going to just order a new 9” from Currie rather than scrounge for a donor.

For the rear end, my plan was to stick with leafs and do a 4.5 mid-eye, Koni shocks, and do a Watts Link. The Fays2 has been recommended and I see Open Tracker offers one as well. Does anyone have any recommendations? Also are there any good sites/videos, etc that cover installation on a 65-66? I haven’t found much and it may be helpful. I’m familiar with the operation of the Watts Link, just not sure what all the installation will require and how it will work on the 9”. All the ones I’ve saw in person were on 8.8s. I’d like a stance similar to the other car pictured.

 

[c2fx]

Since this forum is predominately newer mustangs, I'd recommend the vintage mustang forum. There is a "track" sub-forum where you will be able to get some great information on your specific requirements. I'm not sure if it's still active, but corner carvers also had a lot of good information and knowledgeable users with vintage experience.

My .02...I would take a look at at the class requirements for SCCA. The watts may push you into a different class as they originally had panhards, as far as I know. If you end up going the panhard route, you may be able to keep your 8" rear end. I think there is a lot of internet lore that these are brittle little rear ends that break all the time. I have found them to be quite stout, as well as lighter and more efficient than a 9". I've had an 8" behind a built 351w and T5 in my 70 mustang for 8 years not and have not had any issues...albeit no slicks or 3000 rpm clutch drops, etc... If you're hardcore racing all the time, do what Shelby did and put in a 9". If not, an 8" may be something to consider.

I bought a 66 coupe project about 2 years ago as well. I got all my suspension bits from John at Opentracker. Great guy to work with and cannot recommend him highly enough. I got all new front control arms, springs, strut rods, rear leafs, bilsteins, disc brake kit (front and rear), export and monte carlo brace from him. Street or Track is another reputable shop that knows how to get old mustangs to handle. Shaun is the guy you want to talk to there.

Good luck with the build! My handle over on VMF is cavboy78. I think I've seen you post over there before.

Matt

 

[xr7]

No panhard bars on leaf spring mustangs. The leaf springs are also the control of lateral location. A panhard bar or watts linkage may help in these installations. The leaf springs may work for lateral location but its probably not the best solution.

 

[c2fx]

maybe the original gt350s did not use panhards, but they were used on the trans am mustangs and cougars later on.

 

[xr7]

Just referring to production cars not having panhard bars.

 

[blacksheep-1]

Dude, I've had my hands all over those cars, including 65 through 69 Shelbys, Cobra Jets , Mach 1's, and Sunbeam Tigers,and Boss 302s. IF I were you, I'd just duplicate what Shelby did, under/over ride bars, a PHB , a cable to limit suspension movement and adjustable shocks and call it a day, In the front, you will need to lower the upper control arm up 1 inch on each side, then build a 1/4 inch plate to go between the shock tower to the (for lack of a better term) frame on the strut tower, under the upper control arm. Use an export brace and see where it all goes, I think you will be pleasantly surprised. If you wan to go all ape**** on it then Detroit Speed will be your source IMO.
You won't see many Watts on 9 inch diffs because to do it right, it will require fabrication, the 8.8s, all you need is to slap the watts cover on and throw some speedy dry under it when it starts leaking.

 

[BoulevardofRustedDreams]

I feel pretty set on the Watts Link. What fab work is required for the 9”? I did run across Mustangs to Fears kit for $2600 that looks interesting. However it deletes the leaf springs in favor of arms and coilover. The Opentracker kit is quite abit cheaper and appears to be for use with leafs as I want.
For the front I am already planning a gusseted/blue printed set of road race arms from Open Tracker with roller perches, the larger Shelby drop, and manual rack and pinion. I’m ordering the shock tower and export brace reinforcements from OT along with subframes/x brace/safety loop. Once all sheet metal work is done a cage should be the last big step for the chassis.

 

[blacksheep-1]

I feel pretty set on the Watts Link. What fab work is required for the 9”? I did run across Mustangs to Fears kit for $2600 that looks interesting. However it deletes the leaf springs in favor of arms and coilover. The Opentracker kit is quite abit cheaper and appears to be for use with leafs as I want.
For the front I am already planning a gusseted/blue printed set of road race arms from Open Tracker with roller perches, the larger Shelby drop, and manual rack and pinion. I’m ordering the shock tower and export brace reinforcements from OT along with subframes/x brace/safety loop. Once all sheet metal work is done a cage should be the last big step for the chassis.

well, if you must have a watts, and I personally think they are a waste of money, then you need to go with the full zuit coil spring deal, which leads to coil overs..which leads to rebuilding them every 20K miles, it's just a pit at that point. I would run an electric power steering rack, and you really really need to lower those upper control arms and weld in those braces for the front.

http://www.mustangandfords.com/how-...-buck-handling-tech-how-to-do-the-shelby-drop.







that right there, with an export brace, will transform that car

https://www.cjponyparts.com/flaming-river-rack-and-pinion-power-steering-cradle-kit-with-column-pump-right-hand-drive-small-block-v8-1965-1970/p/FR328PWRH-V/?msclkid=f07b3d3ee9841d7770456384c8b3d293&utm_source=bing&utm_medium=cpc&utm_campaign=New%20Bing%20Shopping%20Ads&utm_term=1101201852196&utm_content=All%20Products#221=2042&year=1966

 

[blacksheep-1]

Here's a nicely done car, No Watts

Full-Tilt Road-Race Mustang

Harley Padilla’s “baby” is a full-tilt 1965 Mustang built to decimate road courses.

www.mustangandfords.com

 

[TMSBOSS]

I saw a program on MT TV where they changed and relocated the upper control arms on a 1969 Mack 1 to make the geo ether work. It was a great design when it came out, sort of. The light weight lower control arm is also a concern.

If you want to go all in at the front, Cortex makes a system. Stand by for sticker shock. https://cortexracing.com/product/xtreme-grip-vintage-radial-x-front-suspension-system-64-66-mustang/

 

[Grant 302]

I saw a program on MT TV where they changed and relocated the upper control arms on a 1969 Mack 1 to make the geo ether work. It was a great design when it came out, sort of. The light weight lower control arm is also a concern.

If you want to go all in at the front, Cortex makes a system. Stand by for sticker shock. https://cortexracing.com/product/xt...t-suspension-system-67-70-mustang-and-cougar/

The OP has a ‘66. Not gonna work on his car.

 

[Norm Peterson]

I feel pretty set on the Watts Link. What fab work is required for the 9”? I did run across Mustangs to Fears kit for $2600 that looks interesting. However it deletes the leaf springs in favor of arms and coilover. The Opentracker kit is quite abit cheaper and appears to be for use with leafs as I want.

A Watts link (or a PHB, for that matter) paired with leaf springs looks to me like a band-aid for the leaf springs not being all that stiff laterally. The fact that there is some lateral leaf spring stiffness likely gives rise to unwanted rear roll resistance outside of a narrow range of suspension heights either side of where the PHB-defined rear roll center height coincides with the rear roll center height as defined by the leaves. "Competing roll centers" (an easy but technically inaccurate way to describe this; some might use the term "bind", which isn't any more accurate) is rarely desirable unless you're roped into using it by competition class rules that won't let you do the job a better way.

It seems to me - Mustangs to Fears apparently agrees (and even Opentracker mentions using a 3-link in combination with their Watts link) - that if you're going to rigidly define the axle's lateral location, you might as well go all the way to having rigid links geometrically define the other three axle motions that don't rely on spring/bar/shock stiffnesses (these being fore/aft location, roll steer, and pinion angle change). This also separates the suspension spring functions (controlling vertical travel and roll, the last two axle motions) from the four suspension location functions, which is a good idea for a number of reasons.


Norm

 

[byronj]

id reach out to Cortex. Filip there built a pretty sweet Mustang like yours and it was a terror on the track.

 

[blacksheep-1]

A Watts link (or a PHB, for that matter) paired with leaf springs looks to me like a band-aid for the leaf springs not being all that stiff laterally. The fact that there is some lateral leaf spring stiffness likely gives rise to unwanted rear roll resistance outside of a narrow range of suspension heights either side of where the PHB-defined rear roll center height coincides with the rear roll center height as defined by the leaves. "Competing roll centers" (an easy but technically inaccurate way to describe this; some might use the term "bind", which isn't any more accurate) is rarely desirable unless you're roped into using it by competition class rules that won't let you do the job a better way.

It seems to me - Mustangs to Fears apparently agrees (and even Opentracker mentions using a 3-link in combination with their Watts link) - that if you're going to rigidly define the axle's lateral location, you might as well go all the way to having rigid links geometrically define the other three axle motions that don't rely on spring/bar/shock stiffnesses (these being fore/aft location, roll steer, and pinion angle change). This also separates the suspension spring functions (controlling vertical travel and roll, the last two axle motions) from the four suspension location functions, which is a good idea for a number of reasons.


Norm

I've run several cars with the leaf spring/ PHB combination, the leave's sideways movement creates all types o f issues with the spring rates, as an example, take a hand saw, bend it, and it's pretty consistent, now introduce a side load on that blade and you will see what I mean, the rate becomes unmanageable. Keep in mind, when this car was introduced, leafs were the standard issue, spring wrap that creates wheel hop was a problem as well and shock technology basically didn't exist. HOWEVER..that didn't mean you couldn't get it to work, use soft springs, which will allow tread compliance, and then you must restrict sideways movement, wrap up, limit body roll, (and those cars didn't use a rear sway bar either), the early 65 shelbys used "override bars" in 66ish they went to "underride bars" to get rid of spring wrap,(wheel hop both under acceleration and braking) staggered shocks came along later which also helped. In order to control body roll, the solution was elegantly simple, a piece of cable around the differential, attached to the body.

http://tractionmaster.com/

 

[Norm Peterson]

I've run several cars with the leaf spring/ PHB combination, the leave's sideways movement creates all types of issues with the spring rates

Understood. I've owned a couple of leaf-sprung cars, and from what I remember about suspension modification for those was aimed at making the leaf springs behave a bit more like a link type of suspension at least as far as control of rotation in side view was concerned.

This leaf-sprung car didn't put out enough torque to need any help in the spring wrap department for any driving I ever put to it.




Norm

 

[BoulevardofRustedDreams]

Thanks for the input so far. So I had one local guy steering me toward Maier for their rear end suspension which uses their springs and panhard. I’m still not entirely settled and this seems to have more varying opinions than asking what’s the best motor oil lol. I may look also at the MTF setup with the lower arms that replace the springs. This is fairly new to me as the only cars I’ve ever owned have been 66-71 Mustangs with leafs and close to stock suspension. If a link/Watts setup, do all of these coil overs need regular rebuilds?

 

[c2fx]

Thanks for the input so far. So I had one local guy steering me toward Maier for their rear end suspension which uses their springs and panhard. I’m still not entirely settled and this seems to have more varying opinions than asking what’s the best motor oil lol. I may look also at the MTF setup with the lower arms that replace the springs. This is fairly new to me as the only cars I’ve ever owned have been 66-71 Mustangs with leafs and close to stock suspension. If a link/Watts setup, do all of these coil overs need regular rebuilds?

I would just call the shops and talk to them directly. Shaun at Street or Track, John at Opentracker, and Maier all have a tremendous amount of experience racing vintage mustangs. I have talked to all of them and they are very willing to listen to your goals and help you get there. MTF is a great shop and I have some of their stuff, just not sure how much focus/experience there is on racing there. I think their wheelhouse is general performance/restomod builds.

I have the QA-1 single adjustables on my '70 since 2008 and i have not had to rebuild them yet. I did have to ship one off because the adjustment knob seized, but that was it. Like all things, the frequency of rebuilds depends on mileage and usage.

 

[Silver LS]

Mike Maier Inc has some good ideas and suspension parts for these old Mustangs. They were developed while racing and winning.

 

[bpracer]

No problem running a panhard rod with leaf springs. My vintage car felt much better when it was installed. A-Sedan rules are more lenient than GT350 B-Production rules for the most part. Move the inner fender wells to the edge of the frame rail, use narrow leaf springs moved inwards , panhard rod and some sort of torque rod. Then you can stuff a bigger rear tires in there. While I think this totally illegal for BProd, it’s “legal” in many organizations. Check with group you are building the car for their rules.

There are definitely two camps for suspension theory on these cars, soft springs and very stiff springs. You should check out Chip Hanes in Colorado, who’s father Walt, won the 66 SCCA BProd championship. Their cars are very fast but very different from Cobra Automotive for example. Pick one theory, and it may depend on your home tracks.

 

[blacksheep-1]

No problem running a panhard rod with leaf springs. My vintage car felt much better when it was installed. A-Sedan rules are more lenient than GT350 B-Production rules for the most part. Move the inner fender wells to the edge of the frame rail, use narrow leaf springs moved inwards , panhard rod and some sort of torque rod. Then you can stuff a bigger rear tires in there. While I think this totally illegal for BProd, it’s “legal” in many organizations. Check with group you are building the car for their rules.

There are definitely two camps for suspension theory on these cars, soft springs and very stiff springs. You should check out Chip Hanes in Colorado, who’s father Walt, won the 66 SCCA BProd championship. Their cars are very fast but very different from Cobra Automotive for example. Pick one theory, and it may depend on your home tracks.

Absolutely true, the light spring guy was an engineer named Herb Adams, who felt that the softest springs were the way to go, then control them with the sway bar, Dick Guldstrand, used stiffer springs, felt all should work together, 2 totally different theories. Of course shock technology was none existent back then.