Used that piece to nail down the dimensions of that upper strut tower.  The next piece simulates this with a bit more metal that I can bend and gusset to support the bar that runs across the top of the motor.  Here’s a mockup with an old piece of chromoly roll cage tubing actually left over from the original yellow “bee”.

I removed the plastic fresh air vents from the cowl of the car.  This allows access to the backside of the firewall without having to come up from inside the car.

I prefer to mock up in wood if I can before I start ordering and cutting steel.  So, lots of careful measuring followed by cutting everything either too small (the holes in the middle of the strut tower plates) or too large (everything else) and then very carefully sneaking up on the correct lengths/angles using the sanding belt/disc.  I think I’ll be using 1/8″ plate and 1.5″ x .75″ rectangular tubing.  It should look like this.

Now for the firewall connection.  This piece will be bolted to both the vertical part of the firewall and to the horizontal “lip” with reinforce on the backside of each connection point.

A bit of geometry hell here – I made this wooden piece 3 times before I got the lengths and angles correct – compound angle on the strut tower side.

Learning curve – only took two tries to get the firewall bracket on the driver’s side correct.

And, I was able to use one of the two ‘failed’ attempts on the passenger side support strut on the driver’s side. Angles matched up perfectly — I simply had to lengthen it a bit.  If you look closely at the picture above, you can see the additional piece I glued on.

On the second plate, the vice handle gave up the ghost at about 70 degrees….

So I had to resort to clamping it in the vice and breaking out the BFH.  Worked — here are the angles on the car.

On to the firewall tabs.  Using my wooden mockups – I bent up some easy-to-bend aluminum strap to confirm angles.  I then used the aluminum bits as ‘gauges’ to measure the progress of my bend in steel.  It’s a compound bend – about a 96 degree bend coming off the firewall; and then you have to tilt the piece in the brake – 3 and 3.5 degrees – to account for the curve in the firewall.  This allows the two tabs to come ‘straight’ off the firewall – parallel to the longitudinal axis of the car.  It just looks better.  The aluminum gauges – 

Final bends.

Carefully marked/drilled holes in brackets and firewall for the bolts.  Always a bit tense drilling into perfectly good body parts.  Really happy with the fit.  Sits completely flush in both planes.  I’ll cut gussets for these tomorrow.

Here’s the gusset cuts/fitting for the top plates.  The goal is no gaps because you can’t weld air.

Stay tuned for Phase 2 next week.  Sunday night post.