Technical Steering box dilemma

Akerman with tie rod in front.

Not impossible but can't be done with stock parts. Not sure if the kit works or not. but a little time mocking it up and checking with strings like the pic shows will tell you

 

You do know there's no front or back to the Speedway axle kit? So you can simply flip the whole axle 180 degrees, or pull the spindles and flip them side to side. And the zerks being blocked means nothing. It's a simple case of turning the wheels one way or the other to get to the zerks when you need to grease them.
Flip the axle, or swap the spindles. Then move the tierod assembly to the rear.
You don't need to have a reverse steering box either. You simply point the pitman arm forward if the box is behind the axle, or point it back if the box is ahead of the axle. Nothing exotic needed.
And it's a lot easier to relocate the radiator than it is to try to clear the sump on your pan! You can raise it just a bit, as long as it stays under the hood. Then locate the steering box to the front side so it's not an issue with anything. This is my front side steering setup on my '39 Chevy, which uses a very similar frame setup to your car.





Disc brake calipers can also go front or rear if they are in the way of the steering arms.

 

If the shackles flipped down then you started out with too much angle on them when you mocked them up. The Speedway shackles are puny, but it's not their puny material that caused them to flip down, it's your installation that's to fault. Need to be closer to vertical, so once the weight is on it they will sit correctly.

 

To get the correct Ackerman with the tie Rod in front, the tierod ends need to be in farther than the brake backing plates will allow. Do not do it!

 

No brake backing plates. It's a disc brake axle, not a drum brake setup. So it is possible to get the Ackerman correct, as Speedway does sell steering arms that are for their axles that put the tierod ahead of the axle. And as I mentioned, one of my cars has the tierod up front, and I made up new steering arms to get the Ackerman corrected for that car. Mine is also disc brakes in front.
And the ends need to be out further, not "in farther".