Camera stick use aside, if you're ambitious you could build a set of Caltrac clones - https://www.youtube.com/watch?v=HXUE8vu11PI

One of negatives on the Drake bars is the single shear bolt setup.  However, breakage is probably related to HP, traction, and excessive use.

Right eye on March 18 left eye on the 25th.  Still won't correct looking at the arrow on an angle finder the wrong way.  

Did you install the spring perches or did they ship the new axle to you with the perches welded on?  Is the axle sitting properly on the springs?  Is the car on the ground at ride height or is the axle hanging down?

if the pinion flange is indeed 5 degrees down it is way off,  I'm not sure I trust your reading on the trans.  You might also confirm with a reading taken along a valve cover with the level held level side to side.  Or, you can also try to get a reading off of the crank pulley.  It looks like you may need a 4 degree angle/wedge shim to bring the pinion flange "up" but I'd try to figure out why it is sitting so low in the first place.  

Report back what you get on a valve cover or some other point on the engine.  Don't use the air cleaner or carb flange as they are usually angled at about 3 degrees so the carb will sit level when the engine angles down.  Are you running stock-style engine mounts?  Do you have an aftermarket trans mount?  Do you have big tires in back that is angling the car down in front?

You can't run it like that.  You may be able to find a driveline shop that does driveline setups rather than a generic chassis shop.  And, Is your driveshaft the correct length?  If it is too long it could be forcing the pinion down.

Steve provided the link you needed above.  All of the information you need is found here:

https://mustangsteve.com/products/cobra-rsm

https://cdn.shopify.com/s/files/1/0847/8392/3488/files/04._INSTRUCTIONS_COBRA-RSM_COBRA-RLG.pdf?v=1706238996

All of the parts can be found at Rockauto.com or other site like Summit.  I trust these over many Ebay sites.  

If the instructions and parts list provided (which includes model years), contact the MustangSteve crew https://mustangsteve.com/pages/contact

So, to further clarify - order the bracket kit from MustangSteve.com, use the instructions to determine the parts you'll need, order the parts, and put it together.

It is easy to measure your engine/driveline angle and your current pinion angle.  There are even apps on phones to let you do it.  Measure first and determine if you even need the angle changed.  There are a lot of variables - spring type, suspension type (link versus leaf), etc., but if the pinion is 1 or 1.5 degrees "down" from the engine it will load up and be right where you need it.  Leaf spring shims are readily available to raise it up or down and are easily installed with a helper if needed.

Why do you think you have driveline angle issue?  Are you fighting a vibration problem?  Are you confident that the pinion angle is responsible?

At a minimum I would measure it yourself rather than taking it to a shop with an open checkbook.

https://support.apple.com/guide/iphone/use-the-level-iphbd435673d/ios#:~:text=Use%20your%20iPhone%20to%20determine,such%20as%20a%20picture%20frame.

https://apps.apple.com/us/app/toolbox-tremec-u-s/id6466313595

Do you have a part number for the kit?  March has fairly good descriptions of parts requirements and what fits on its web site.  Some will and some won't support a mechanical fuel pump based on the part number and the type of power steering pump that it supports.

Depending on moon phases and sun spot activity, a clear fuel filter will not always be full of fuel when the engine is running.  There is enough fuel flow to keep it running, which isn't much at idle.  When the engine had the same symptoms with two different methods of fuel delivery and a multitude of new parts, it likely had to be something else.  When a distributor module flakes out, it won't cause the engine to slow down so much that the filter won't be full - it'll quit.  I bet that the fuel filter still doesn't always appear to be full now that the ignition module is fixed.  A number of MSD systems will also fail in the same manner - run for 30 minutes and quit and then restart after an hour - until they eventually quit altogether.  I'd make sure that the Mallory setup is getting the proper voltage for that particular model.  Some require straight battery voltage with no ballast and some require a ballast resistor to keep them happy.  A timing light is helpful.  If it quits, either grab the coil wire or even better hook up a timing light.  If the light doesn't flash while cranking, the ignition quit.

Did you try the two-person method?  I've had several where vacuum bleeding wasn't successful but push-push-hold worked.  Sometimes pushing a bubble through under pressure will clear air out.  Check the condition of your rear brake hose and try to minimize any high loops that can easily trap air when vacuum bleeding.  

What is your full ignition setup?  Some ignition module failures will show similar symptoms.  You could try to keep it running using a squeeze bottle and dribbling fuel into the carb.  If you have a timing light, trigger it while the engine is running and see if the ignition quits (light stops flashing) before the engine stops.  If it runs out of gas it would keep firing until it finally stops.

Not all C4's do this from what I have read.  With my friend we also had a pump/case mismatch due to parts used from different years.  If I recall there were some drain holes/paths that didn't quite match up.  The correct pump was installed but the puddle persisted.  The check-valve cured.  One article stated that it could be in the outlet to the pump so you may want to do some more searches to see which side provides the best results.

With a Hyfire or other spark box you will not see 12 volts at the coil so the lack of 12 volts when the engine is not running is not a valid test of the box.  High voltage to the coil will only be delivered when the ignition fires.  You should confirm that you do have 12 volts coming from the ignition switch.

To verify your coil and spark box, conduct the basic white wire test as described in the instructions -
CHECKING FOR SPARK If triggering the ignition with the White wire:

1 Make sure the ignition switch is in the "Off" position.
2. Remove the coil wire from the distributor cap and set the terminal approximately 1/2" from ground.
3. Disconnect the White wire from the distributor's points or ignition amplifier.
4. Turn the ignition to the On position. Do not crank the engine.
5. Tap the White wire to ground several times. Each time you pull the wire from ground, a spark should jump from the coil wire to ground (the LED should also blink). If spark is present, the ignition is working properly. If there is no spark skip to step 6.

Wiring should be similar to the bottom of page 8 - https://documents.holley.com/690.pdf 
Since your system has run for years it must have been wired correctly.

Steve is probably on track with the Petronix and the white wire tap test will help prove that.
 

Not sure I would trust photos posted in ads.