In this post I'll detail how I notched the 67/68' shock towers.
I used a discarded pair of 65' Mustsang coil springs to help determine the amount of spring-to-shock tower clearance before doing any cutting of the tower. One full coil was cut off of one spring so it could be positioned by hand:
The spring was at its closest when the UCA is extended and resting on the frame (its full downward location.) The closest point was located just above the
LCA pivot where I measured 3" to the tower.
The 2nd spring had 3 coils cut off. It was installed using blocks to hold the UCA upward firmly against the bumpstop:
IIRC, there was 3/4" of free space at the top of the tower. With that info, I felt confident in doing some cutting.
From the beginning, I didn't want to do the typical press brake type 90* flat plate notch that is so often done. At the very minimal, I wanted the angle change above the UCA to be rounded. Also I wanted the plateau over the 2 UCA to angle slightly downward toward the engine compartment. None of the local machine shops had the dies to create a quickly rounded 70*-90* angle so instead I had them do something a little different. Basically 2 press brake bends (20* and 70*) 5" apart on a pair of 13"x16" sections of 1/8" (11ga) sheet metal. There was also to be some rounding on the 5" center section between the bends. Here is what they came up with:
When I compared the plates to the shock towers I really didn't like this 2 bend design as much as I had hoped and ended up trashing the idea. Since I originally had my heart set on a rounded angle, I got creative. With a quick trip to the nearest scrap yard I picked up a suitable length of thick walled 4" square tubing that had rounded corners to use as a jig pattern:
OK, maybe I went overboard on the length, but it was cheaper (and faster) to take the whole 6' section rather than have them cut it shorter. Perhaps it may be used for some other project in the future.
I began by marking the bend location on a 1' square piece of 3/16" plate steel:
This plate was clamped to the square tubing, sandwiched with a separate 1/4" plate on top to help hold the 3/16" plate firmly in place. The marked line is placed parallel with the bend on the square tubing:
The lined area of the plate was heated cherry red with a cutting torch and then bent with several strikes from a decent sized hammer:
This is not a fast procedure as it required several minutes to heat the metal hot enough to bend the plate. All that metal literally sucked up the torch heat in an effort to dissapate it. Still, the result was good and it gave me the nice clean rounded bends that I desired:
I was then ready to notch the shock tower. It was cut using the same techniques that others have documented in the past, such as in this thread:
http://www.fordmuscleforums.com/suspension-articles/498392-notching-shock-towers.html
First the shock towers were covered with masking tape in order to make it easier to make cutting lines:
1/8" holes were drilled to verify some locations and to act as a guide. The first cut was inward 1/2" at the top of the tower, 2 1/4" at the bottom, and a horizontal cut was made 1 1/4" above the UCA pivot bolt holes. Both a saws-all and an angle grinder were used to remove the center section of the tower:
Its hard to tell, but the lower cut was done on a downward angle toward the engine compartment.
I was not yet satisfied with the rounded bend design as it looked out of character being so darn flat above the bend. I stared at the A shaped piece that I had just cut out and wondered if I could incorporate some of it into the design, specifically the upright rounded corners where the tower meets the new sheet metal insert. I did a little hacking on the A shaped piece and saw that my idea had merit. After a little more trimming with the saws-all and grinder I came up with a solution that I haven't seen done before: