Introduction
After a lot of reading and data gathering, I have come to some conclusions regarding modifications required to place a Land Rover MAF inside a larger intake tube, such as with the 5.3 LS.

Generally, if the Rover MAF is stuck in a larger tube (e.g., factory 3.0 in to 4.0 in, the values derived in the Rover ECU will be lower than normal. This is not ideal for several reasons. The readings are also highly influenced by the presence of MAF screen, which converts turbulent flow to laminar flow.

Therefore, to counteract the effects of using the Rover MAF in a larger tube, two things are required: (1) a larger MAF screen to put the air in the larger tube back to laminar flow an inch or so before the sensor and (2) a signal amplifier to put the signal values closer to where they need to be. A larger MAF screen with different sized cells (e.g., the 1/4 in ones suggested below) actually can get the values fairly close on its own without the amplifier.

Using an amplifier in this way can also be used to overcompensate the airflow readings, which results in more aggressive shifting (e.g., gears hold longer, downshifts occur sooner).

I've put together a small guide below if others want to try this modification. I'll supplement this as I learn more.

Disclaimer
This is a substantial modification — I’m not responsible if you fry or toast something. Not adjusting this properly could ruin your transmission. This has not been tested much and the long term effects of running it have not been established.

Data Gathering
Before you start, using the MAF in the factory housing, use a scan tool to see what the readings are at idle (750 rpm). It appears to be roughly 6 g/s. Find generally what some other readings of your MAF are at other power levels while driving. Consider taking a video to record MAF output and torque from the Rover ECU.

Amplifier Construction
The amplifier is a rail-to-rail, variable-gain design.

Parts:
Breadboard: Pigtail Plugs: Operational Amplifier: https://www.mouser.com/ProductDetail/595-TLV2372IP
10k Resistor: 10k Potentiometer:
Notes on diagram, my goal is to replace this with a better one soon:
Top of Op-Amp indicated by circle. Dots indicate connection of circuit. No dot, no connection.
R1 = 10k resistor
R2 = 10k potentiometer (center pin connected to MAF signal out, pin underneath dial connected to R1 and Op-Amp pin 2, other pin unused)


I usually use the following colors on breadboards generally:
Red = 5V
Ground = Black
Signal In = Green
Signal Out = Blue

External Connections
Splice the complementary pigtail into these connections:
5V = supplied by Land Rover C0636, Pin 10, former TPS 5V supply (color: red)
Ground = supplied by Land Rover C0636, Pin 25, former TPS ground (color: red with black stripe)
MAF signal in = connected to portion of Land Rover C0636, Pin 23 from MAF (cut wire, splice portion from engine here) (color: blue with green stripe)
MAF signal out = connected to portion of Land Rover C0636, Pin 23 to ECU (cut wire, splice portion to ECU here) (color: blue with green stripe)

MAF Screen
A 4 in aluminum honeycomb air straightener screen from PerformanceMRP with 1/4 in cell size seems to work well.
PerformanceMRP’s website is here: https://performancemrp.com/i-3049756...er-screen.html
Their eBay item: https://www.ebay.com/itm/263049763984

You can cut the screen to fit inside your air intake tube. The screen should be about an inch or so in front of the MAF cartridge in a straight section of pipe.

Calibration
Once built and connected, install the MAF in the larger tube with the MAF screen. Use a scan tool to see what the readings are at idle (750 rpm). It will be slightly lower than previously (like 5 g/s). Turn the **** on the potentiometer to adjust the amplification higher or lower so that the idle reading is around 6 g/s at 750 rpm. This appears to be a good starting point with slightly more aggressive shifts and longer holds in gears. The more the amplifier is adjusted upwards, the more aggressive the shifting will be.

 

Captain,
Your plans look doable for me. If I order supplies from Amazon I should have enough parts to build 50 amps.😄
I think I’ll see what kind of data I can see using my Foxwell NT530 before I begin. I’m sure questions will be headed your way.

 

@CaptainAaron
Hey just going over this now but noticed all your Amazon parts links have expired.
Are you able to provide new links, or specs for the parts required?

Alternatively, @Tracecollier@yahoo.com are you making these for purchase?

Thanks Fellas!