So, when measuring toe, if you want toe in of 1/8" it means the measurement in the front is 1/8" less than the one in the rear.  This is measured from a common point of reference, say, outside of the outermost tread block on each tire, front, and rear.

Toe is only part of the steering situation though.  The centerlink needs to be centered.  I've read all kinds of crazy methods for this, but what 100% works is to just make sure your tie rods are the same length.  Then, when making adjustments, adjust each side equally.  If afterwards the wheel is off center, just pull it and reposition it.  It was probably reindexed years ago by some well meaning, but ignorant PO or shop. 

With the tie rods the same length and your measurements the way you want them the steering and toe is done.  I will say that 5/16" toe in or out is a lot IME.  Typically you will get scrubbing at anything over about 1/8" in slow turns when running toe in.  Toe in is best for all around driving and high speed stability.  The only place to run toe out would be a tight road coarse or track.  It makes the car twitchy, though turn in is improved (good for tight turns, scary everywhere else). 

I'm with Chaplin on this though, I don't think toe is your issue.  It sounds like tires to me.  I'd consider that carefully, how old are they, when was the last time they were balanced, etc.?  Tires can have plenty of tread and still be no good just from sitting past their expiration date.  Over time they break down internally and lead to all manner of bad handling. 

Last edited by TKOPerformance (2/25/2020 5:43 PM)

Not only tire condition but wheel condition also. Jack up the car and check tire track the same way you check prop track with a nail in the end of a stick. Check both tire and wheel for round and track. If you find one out of track verify the disc/drum too.

Pop would place a jack stand in front of the tire and hold a scratch awl to the tire to scribe a mark as close to center as possible.......I had to spin the tire!! He used that for the toe measurement in front and back.

The alignments I’ve paid for on the Mustang provided a report showing 1/16” per side, not just an 1/8” overall.

I usually put a board through both front windows and clamp the steering wheel where I want it going straight down the road before any toe setting. Then, just like I watched AJ Foyt in gasoline alley set the toe on his Indy winning racecar put the four stands and monofil fish line around the car at hub height. measure at front and back to hub center and play with the stands until you have a perfect rectangle centered around your car.
Now, you  can see if your front and rear axle positions are centered with the car or not (oval track racers don't always center things). Setting toe is easy now by measuring from string to rim at front and back of rim. 
OBTW I watched Mark Donohue do the same thing on his winning car at Indy.
Most of my experience with shimmy though had more to do with caster.
Anyway if you split your total toe evenly between and adjust both sides your car will go down the road straight with the steering wheel centered. If you do a lot of super slab driving you may want t add a little bias to account for road crown.

Probably nothing worn in the front suspension since it is all pretty new. I'll get the tires rotated and balanced before the Bash to see if that help.

As for Toe, I have some nice homebrew toe plates that make measuring toe easy. I understand toe and why we need it. I just don't know how to explain what my question is. 

I don't know DC other than from what I read here, but I'm pretty sure he knows that the steering box needs to be centered before doing the toe. I'm guessing his box is centered when the steering wheel is in the straight ahead position.

RV6's question was whether the toe was set in degrees or inches, and that depending on the diameter of the tire, whether the difference in actual toe with a larger tire when set at 1/8" would matter in the degrees it was at, since it'd be different from a smaller diameter tire. Confused yet?

I set my alignment by first setting the rear axle thrust. I marked the center of the radiator cross member and dropped a plumb bob to the floor. From the axle end centers I dropped plumb bobs to the floor, and used triangulation to get the axle centered and 90° to the center line of the chassis.

Once the rear axle was in the  proper position I set the front end alignment. I started with a centered steering box, and measured to make sure the tie rods were the same length. Even using greased sheet metal plates as turn tables, sometimes when I turned the tie rod adjuster, that wheel remained straight, and the adjustment turned the steering box. This drove me nuts till I discovered what was happening.

I've thought of having the alignment checked at a shop. But since it handles great, tracks straight at over 100 without input from the driver, and the tires wear even, I figure I'll spend the saved time watching tv.

Bearing Bob wrote:

I don't know DC other than from what I read here, but I'm pretty sure he knows that the steering box needs to be centered before doing the toe. I'm guessing his box is centered when the steering wheel is in the straight ahead position.

RV6's question was whether the toe was set in degrees or inches, and that depending on the diameter of the tire, whether the difference in actual toe with a larger tire when set at 1/8" would matter in the degrees it was at, since it'd be different from a smaller diameter tire. Confused yet?

I set my alignment by first setting the rear axle thrust. I marked the center of the radiator cross member and dropped a plumb bob to the floor. From the axle end centers I dropped plumb bobs to the floor, and used triangulation to get the axle centered and 90° to the center line of the chassis.

Once the rear axle was in the proper position I set the front end alignment. I started with a centered steering box, and measured to make sure the tie rods were the same length. Even using greased sheet metal plates as turn tables, sometimes when I turned the tie rod adjuster, that wheel remained straight, and the adjustment turned the steering box. This drove me nuts till I discovered what was happening.

I've thought of having the alignment checked at a shop. But since it handles great, tracks straight at over 100 without input from the driver, and the tires wear even, I figure I'll spend the saved time watching tv.

How were you able to make adjustments to where the axle housing was located? 
 

I always count turns lock right to lock left and set wheel in middle before tightening the clamps that hold the steering wheel centered. I put two punch marks on chassis where I can drop plum when I built the car to define car centerline. Rear axle and front suspension were installed to that line defined by those marks. That also makes rechecks easy until I fold the chassis up into a little ball someday.