Installing the Lightning 80mm MAF
The 80MM Lightning MAF is the stock sensor on the 5.4L F150 Lighting from '99-'00. It uses a unique sample tube setup which allows for more accurate airflow measurement while expanding its dynamic measurement range for its supercharged application. Having said that, it is also a very good value when considering a MAF upgrade for 70MM units(or smaller) on a limited budget. List price on 6-2-2000 was $147.73. Discounted from your favorite dealer it can be relatively cheap.
YOU MUST have the transfer function of the Lightning MAF put on your EEC/PCM/CHIP for proper air/fuel ratio and engine function. It is not just a hardware swap.

This is the inlet side view of the Lightning MAF (L-MAF), Ford PN XL3Z-12B579-AA. It uses a flange mount on the front which is the standard flange for F150/F250 and 4.6L Mustang airboxes. Adapters can be purchased to allow for large open cone filter attachment. These are the only mounting points so be prepared to come up with something to hold it. The bore of the MAF is actually smaller than some other MAFs, but it is venturi shaped to control air velocity tighter.
Note on filter configuration. The stock configuration has air entering this meter from an airbox using a flat filter. Flow is more centered on its bore than the TBird style airbox. Changing the airstream dynamics can affect the meter's accuracy, so sticking with the factory configuration is a good idea. A cone filter seems to be a very good fit for this application, but many have successfully adapted their L-MAF to the stock TBird airbox with acceptable results.

This shot is a back to back comparison of the outlets of the L-MAF on the left and the stock 70MM MAF used on my '95 Thunderbird. The outside diameter of the L-MAF exit is about 3.6" or about 90MM. A 3.5" silicone hose fits very snug over it.

Here is the L-MAF attached to a Mustang Style K&N filter. I used a piece of aluminum plate and made all the holes to glue and screw it together. The wiring harness shown is a must-have. The connector on the L-MAF is the late model style.Use F68Z-12A690-AA wire assembly and cut off the other end to allow it to be spliced into the stock wiring. The wiring pinouts match the stock, A to A , B to B, C to C, D to D.
A hint: To attach the L-MAF to a stock T-Bird airtube to the TB, you will need to adapt from 3.5" to 3". Otherwise, you can get a custom intake tube and use the TB boot off the stock airtube(violin case) to attach reversed to the L-MAF and provides a 3" outlet connection. Then you can use the port from the idle air bypass to insert the intake air temperature sensor into the airstream.
Good Luck.