Something else for you to think about.  I spent 13 years in the powersports industry (ATV's and Side x Sides).  Your typical ATV with a Kevlar Belt CVT style transmission, high angle CV joints in the halfshafts, and straight cut bevel gears in the trans and differentials will lose between 35% and 45% of the engines crankshaft power to the drivetrain before it gets to the wheels.  I.E., an 80 Hp 950 cc V-Twin on the engine dyno was putting about 48 hp to the ground on the chassis dyno.  Obviously this is on the extreme end of drivetrain in-efficiency spectrum, but that 32 hp that is lost has to go somewhere.  Generally it manifests itself as heat due to internal friction, and is a big reason why the drivetrain components where not expected to last much over 150 or 200 hrs of operation, equivalent to 5000 thousand miles at most.  Much different than the automotive side of things, but the concepts are the same.  There is a direct relationship with the amount of Energy or Power that is consumed by each drivetrain component and how long it lasts.

I have not used the Flaming River Kit, but there a couple of things that stand out to me right away when I look at it on line.

1.  The Price.  Holy Shit, I am in the wrong business.  $2500+ for a reverse steer Mustang II power rack and a laser cut steel bracket.  They must think we are stupid.
2.  This kit uses a rack with the ball joints at the ends.  With the Galaxies A-arm geometry, this puts the pivot point of the tie rod well outboard of the Lower Control Arms pivot axis.  This will likely lead to bump steer and is a significant departure from the original geometry. 

I built the rack and pinion for my '62 Monterey (same chassis as your '63 Galaxie).  I used a late 80's GM J platform rack (Think 1989 Cavalier, Sunfire, etc).  The advantage of the GM rack is it is center steer.  I fabricated a plate that mounts to the center of the rack, and holds the tie rod ends at the right location so as to not create any bumpsteer or other geometry issues. 

I also fabricated a couple of plates that mounted the rack to the chassis, using the factory GM C-Clamps.  I made my own tie rods using DOM tube, and purchased a set of LH and RH 11/16 taps from McMaster-Carr.  All in, the whole setup was less than $500.  Not the best pictures, but you get the idea.

I used the original FoMoCo Eaton power steering pump, and just had the local hydraulic shop make up a couple of new lines with the right ends on them  For the steering linkage, I cut the rag joint coupler off the end of the column.  Put a support bearing into the end of the column tube and use a Heidt's Double D universal joint and couplers.  I did have to weld a heim joint to the frame to support the steering linkage as well since it took 3 joints to get to where I needed to go.

The one downfall, is the GM rack doesn't have as much lateral travel as original steering system, so some turning radius was lost.  A person could shorten the steering arms on the knuckles to get that back.  I never took the time, and in a 19' long wagon, people expect you to do a 3 point turn in a tight parking lot anyways.

FPA makes a set of headers to clear this particular conversion.  They worked well in my car.  Overall, the car handles really well, and is much more responsive than with the stock bell crank system.

You would have to get the design engineers, manufacturing engineers, tooling engineers, accountants, and managers all in a room and have them explain why the decisions were made.  I can tell you that I have worn a few of those hats for both OEM and Tier 1 suppliers, and quite often the decisions are made as a result of immediate circumstances, even if it is known that they will look foolish in the future.

The other aspect that you have to remember is the OEM is concerned about initial assembly, and initial assembly only.  They care very little about compatibility, ease of service, disassembly, etc.  If they can save a few pennies and increase efficiency on the assembly end, they will make those changes quickly.

Minnesota is a big state, but it looks like you are hoping to find a place near the Twin Cities.  I had used a shop in Brainerd for the driveshaft on my '51 F-1 decades ago, and a quick Google Maps search shows they are also no longer there, so not much help.  Since moving to the Red River Valley, I have probably had a dozen custom driveshafts made or modified by Grand Forks Welding and Machine over the past 15 years or so.  Great bunch of folks to work with.  I am sure if you provide end type specifications, and dimensions they can make something and ship it to you.

Yeah,  Pretty tough to call these "Ford" or "Chevy" motors.  There is some geometry that is similar to or derived from parts of the 385 and BBC engines, but everything is bigger, all billet, and very highly engineered.  Honestly, they have as much in common with a Mack 998 V8 as a Ford 460 V8.

Sounds very similar to the 390 I built for my '76 F250 Camper Special 5 or 6 years ago.  I too wanted a towing cam, something that had a lot of low and mid range torque and would work well with the stock heads and 4 bbl intake.  I ended up choosing a Howard's Dual Pattern Cam (P/N HRC250031-12).  It worked really well, that motor pulled like freight train from 2000 RPM's on up.  It had no trouble yanking my 24', 10,000 lb Pace enclosed along at 65 - 70 mph.  For a 410, you may want something a bit bigger for the extra cubic inches.

Here are the specs.
Year: 1963 - 1977
Make: Ford
Engine: 352-428
Camshaft Type: Hydraulic Flat Tappet
Basic RPM Range: 1400 to 5200
Valve Lift Intake: .525
Valve Lift Exhaust: .525
Duration Intake: 267
Duration Exhaust: 277
Duration at 050 Intake: 213
Duration at 050 Exhaust: 223
Lobe Separation: 112
Intake Centerline: 108

Cool photos Heo.

I have a similar affliction, and even got to spend a few years living and working in North Dakota which is chuck full of ghost towns and other abandoned property.  So much so that multiple books have been written and numerous National Geographic articles as well.