Front suspension question

[ksquared 13]

A guy at the shop working on my car suggested that I modify the upper A arm mount points by lower them by 1 inch and moving them back by 1/16 inch. Said it should improve handling (which is important to me). He said that is what Shelby did. Anyone familiar with this mod? Is it worthwhile? Side effects? Seems like a simple mod especially when the engine is out.

[jmlay 80]

Lots of good reading on this site as well as VMF, & others is you serch for "Arning drop" and/or Shelby drop.

[Grabber70Mach 107]

Try here: http://dazed.home.bresnan.net/drop

or

http://www.opentrackerracingproducts.com/droptemplate/

 

 

IIRC the 1/8th back doesn't apply to 69-70 cars.

[fvike 173]

What it does, is by moving the upper A arm down, is that it makes the arm "longer", and you get more camber gain.

[RPM 1,190]

Me thinks that by lowering the pivot arm, the suspension has less positive camber when compressed and more when decompressed. The ideal static camber according to many Mustang gurus is around -1 degree.

[69gmachine 15]

Moving the arm back will give you more caster, which may be beneficial depending on how you plan to use your car as it will track straighter while increasing the effort to turn, but also provides camber gain in a turn that goes away when the wheel is centered. It can also provide more clearance for a larger tire in a turn so long as it doesn't move too far back. I moved the top back by adjusting my arms out in the front, but of course I don't have stock upper arms.

 

The only down side to this mod is that it will weaken the shock tower slightly. That may not be an issue again depending on how you intend to use the car. There are a few ways to mitigate that;

1) use coil overs that mount to the lower control arm to reduce the lever effect on the shock tower.

2) use an upper control arm with the drop built in like the ones I have or that Total Control has rather than drill another set of holes.

3) lighten the weight of the front end, especially weight above the cam center line (and forward of the wheel centerline for better handling overall).

 

Unless you actually race your car in something like autocross, you probably won't stress the shock tower enough to matter, but the weight on the front end will also effect the stress; more weight = more stress.

[ksquared 13]

Wow - good info! Looks like my Mustang project is for sure going to be a never ending one :rolleyes:

[tony 63C 14]

For what it’s worth ‘ll just say that since rebuilding my front suspension and steering several months ago with new control arms, bushings, idler, tie rods, etc, all back to stock (except roller perch upgrade) and then aligning to Opentracker specs the car handles surprisingly well for an old girl. I’m very pleased with the improvement and this essentially factory stock set up is more than adequate for street cruising. Dare I say, done right these mustangs are respectable handlers for cars of the era.

Cheers,

Tony