Shelby stocker

[thatdarncat]

I’m planning on doing the Shelby upper A-Arm drop on the ‘67 Cougar I’m working on also, mostly for the same reason Mike mentioned, to keep the tires straighter on launch & under power. I intend my car to mostly be drag raced with some street driving for Drag Week. I’m trying to keep everything rules compliant to possibly run in Stock Eliminator in the future too with an engine change. I have the rollerized front suspension parts already. There are different published drawings for doing the drop on the ‘65-‘66 Mustangs and the ‘67-‘70 Mustangs. I purchased the metal template Open Tracker sells for the ‘67-‘70 cars, but mocking it up I was concerned on where it looked like it was going to put the a-arm also. Part of my concern was on what it looked like it was going to do to the caster setting. For drag racing usually you try to put more caster into it. It might be a case of what’s optimum for road racing is different. Anyway, my conclusion was although it would be easier to do the drilling now with my car all stripped down too, I decided it would be prudent to wait until I got it all assembled and at race weight/ride height and make a preliminary check of the front end alignment and see where it’s at stock,  and then make a decision on what is the best location for the dropped holes. There’s not a lot of room for error there, and although doing it that way will be a lot of extra work, I figure it’s better not to have holes in the wrong place to deal with too. Just my observation & plan, I think some of my concerns were the same as Mikes. 

Here’s the template for the two different ways to do the a-arm drop. Which one were you intending to do Mike?

[mike7570]

The new holes will come right up to the edge of that double metal area, but they won't go over it.  At least mine don't...

I have a template but didn't set it in there yet. The 1" may be deceiving now that I think about it. It must be center to center if it stays on the 2 layer area.
I think I'll mark it tonight and see.  Thatdarncat beat me too it, center to center makes more sense. (67-70)

[thatdarncat]

I’ll add too, since there are two different common templates to do the drop, It’s probably also a good idea to ask people which one they used.

[afret]

The template with the holes 1/8" back are for the '65-'66 Mustangs and the other one is for '67 and up.

[Nightmist66]

I did the Shelby drop on mine this time while I had it all apart. I didn't  but any fancy drill template. I simply used a 3/4" wide piece of flat stock aluminum and trimmed it to the exact bolt center to center. I held the piece directly under the center of each existing hole, right up to the edge and made a sharpie mark under the bottom corners of the flat stock. Double checked that the center to center of my new marks matched the existing and then drilled. Since I held the flat stock to the edge of the existing hole and used 3/4" material, it gave me the total of 1". After I got the holes drilled, there were two I believe that did slightly break through the edge of the double stamped metal. I just decided to roll with it. I don't think it will hurt much. I also bought the roller upper control arm conversion kit, roller perches, tubular lower arms.

When I jacked up the lower control arm, I had a magnetic angle finder attached to the rotor and watched throughout the travel. I was very pleased to see the arc stayed within 1/2° the whole time. I am also using the camber lockout kit with interchangeable blocks. I have not had the car back on the ground yet to see how it will all settle.

Also, I am using some 1/4"  steel plate to replace the upper shock mount. This will help with rise, but also limit the compression, because the shock cannot go back up as high. I also made my own adjustable strut rods with heim joints.

[Heo]

I did several shelbydrops. What i do if the engine is out of the car
is i weld the edge where the new hole will be and ground flat before
i drill.  i also weld around the reinforcements 1 inch welds 2 inches apart
and make reinforcementplates that go around the corner of the springtower
like on boss and cobrajet cars. And i weld in an reinforcement plate on the
outside, from under the a arm boltholes down to the framerail at a approximately
45 degrees. The caster you adjust with shimming the upper A arm between the
shaft and springtower

[mike7570]

I make a little progress and I get all giddy about it.  Well it's not often I find time to do some work on the car. Retirement in about 5-6 months! 
The new crank showed up (391 crank still for sale) and I have the block in for machining now and should have a short block ready in a few weeks.
 

[mike7570]

From previous discussion, hole location for Shelby drop. Suspension compression and extension (no spring)
Engine compartment and disc brakes, getting closer. 

[gt350hr]

  The drop does nothing to help a drag car. My first GT350 was a carryover '66 ( 65 chassis) which had factory lowered A arms and my current one ( of 46 years) is a '66 chassis and is not lowered. I saw no difference in "performance" or driveability at the drag strip.
  Randy

[mbrunson427]

Randy, the gain is what was illustrated in the pictures. The camber stays true through the whole up/down movement of the suspension. May not be worth big ET, but when you're racing in a class that hundredths matter a lot.....

[e philpott]

Mounted 1/8th rearward would give a little more positive Castor , that's a good thing on a drag car

[gt350hr]

   I understand , it's just that I never saw any difference. My '66 with standard a arm location has very little camber change , even "topped out" with the wheels off the ground. I did see a change when I changed the strut rods to aftermarket ones with heim jointed ends. I've owned 4 GT350s with factory lowered A arms and three without. Certainly an improvement on cornering .  I have over four thousand passes on this car . I had about 1,200 on the 4 speed car with lowered A arms. Yes I've been drag racing Shelbys a long time.

[Keith Stevens]

Mounted 1/8th rearward would give a little more positive Castor , that's a good thing on a drag car

There isn't really room for reward movement.  I have this done on my 67.

[mike7570]

  The drop does nothing to help a drag car. My first GT350 was a carryover '66 ( 65 chassis) which had factory lowered A arms and my current one ( of 46 years) is a '66 chassis and is not lowered. I saw no difference in "performance" or driveability at the drag strip.
  Randy

I raced my '67 coupe in super street with a stock front suspension and 90/10 shocks, the front end would ride a little high until the finish line, where once on the brakes the camber change would affect the handling some and keep your attention. In contrast my super gas car with very little travel was rock steady through the entire run.
The Shelby drop was easy to do and should help the finish line handling when dumping an opponent

[HR427]

Cool project.  I am putting together a 64 high riser stocker engine as well.  Which crank did you go with?  I ordered a scat with .013+ on the stroke.