Need help spec'ing out new rear suspension in a 1978 Mustang II King Cobra

[ModedCB2]

I spent most of the day reading through post after post of the various styles/types of suspensions being used/sold right now.

Here is the intended use:

* Lots of cruises, long haul drives, back road corner carving.
* occasional Open track and/or random auto-x, but nothing competitive. I simply don't have the time to dedicate.
* I want stance.
* I won't be adjusting this thing all the time, nor do I want a ton of work if I do hit an open track event.
* Full Tailpipes out the back REQUIRED... I will not dump the exhaust and I don't want to go under the live axle.

with all that said... here is what is in the car now.

Front:
*Heidt's wide tubular UP & Low control arms W/Triangulated lower, so no strut arm.
*Arms have been retro fitted with custom poly bushings.
*QA-1 coil-over conversion with the tapered spring & dual adjustable shock.
*1 1/8" Quickor Sway bar, custom poly links.
*Highly modified SVO 15:1 steering rack, offset bushings
*Baer Bump=steer kit
*Flaming river Solid shaft and custom steering column.

Rear currently:
*67-70 59.25" wide 8" axle housing
*Auburn Pro series Dif, 4.10 gears, Moser 5-lug 28 spline axles
*Detroit/Eaton Custom de arched Comp. Handling Leaf Springs.
*Custom turned-down Daystar poly urethane leaf bushings, all 4 corners.
*Billet machined rear leaf shackles
* 13/16" ford rear sway bar with custom poly end links and std poly bar mount links.
* Southside machine Traction device, not a slapper bar

I am getting things ready to dive in this winter to redo the King Cobra. I built it 7 years ago, then it had to set due to life just being life. I am entertaining ideas of an Air-Bar style bolt in system or a modified 3 bar or even the TCI torque arm. Since 90% of the car is done and this will be primarily a complete cosmetic retro-toss back on the build, the hard costs have already been spent. So I am not scared to throw some $$ at the rear suspension if there is a REAL need to.

After reading about Mary Pozzi's success with Leafs, I'm game.... unless there is a significant reason to move on. Ride quality and predictability are paramount to me.

Just looking for some logical opinions on alternate roads to consider. Add a floater to the leaf set up and be done? go 3-4 or torque arm?



I'm just getting sucked down in the mire of all the various discussions. Would appreciate some straight-forward thoughts.

thanks!

Rob

[Randy67]

3-link with Watts link (panhard bar as an alternative). Torque arm would be my next choice.

[John Wright]

If you aren't out looking for that last tenth of a second.....I'd stick with the leafs. There is something to be said for simplicity. Buckle in and drive. You can still play with sway bar rates if you need to tune it some.

[SLO_Z28]

One thing to consider, people spend tons of money switching TOO the mustang II setups, they work really good. I wouldn't go overboard in this car.

[ModedCB2]

well the FRONT is fully sorted, no worries. Its outback I am most concerned with.

Like I said, I don't have $$ burning a hole in my pocket to spend "just cuz". Its a question of if there is something SUBSTANTIALLY better for the rear, based on my use, I m all ears.

I'd just like to see some conversation about the 3-bar or triangulated 4-bar in terms of will it REALLY change both the handling and the ride of the car?

Rob

[78CobraII]

The 'low-buck' approach does indeed work with the Mustang II:
http://www.popularhotrodding.com/fea...i/viewall.html

I'd like to compare rear suspension dimensions with the '65-'66 Mustangs and see how many kits for them would work with the MII with a little modification. The biggest issue is probably the lack of the rear subframe rails in the MII, but a little welding could probably get you over this hurdle.

Leaf springs with the Southside bars or Caltracks and a Watts Link should be all you need on reasonably smooth surfaces. Rough roads (say a street-based road race) would call for a more compliant rear suspension (such as IRS).

[Bryce]

There is nothing wrong with leaf springs. As long as they are not taking up room for tires. That was the main reason I design my own 3-link with watts. I needed that extra few inches to fit a 275tire.

I would still use a watts with the leafs and spherical bearings at the attachment points. I would get a stiffer front section of the leaf spring to reduce wheel hop.