G'day Tom (@tcinla),
I was hoping that these two (F and L) would be an easy build while I anticipated a bit more effort on the Ns with the need to eliminate the rear canopy to fuselage join (which is often ignored in builds).
However, the pedant in me couldn't live with the strange lower fairing on the F and L.
The Osprey book "P-40 Warhawk Aces of the MTO" (Aircraft of the aces 43) has a lot of pictures of Fs and Ls and I think I have a reasonable idea of what is needed here.

And I've just stumbled across this:
https://forum.largescaleplanes.com/index.php?/topic/25959-warbird-productionsgrey-matter-aviation-132-p-40fl-nose-conversion/

You're doing a great job on the P-40's Michael, I used the pic from the Squadron/Signal book " Curtiss P-40 in Action", to correct the AMT mistake. That's quite a project for you to do 4 at a time. Keep it up I'm enjoying the view. One can never build too many P-40's.

2 attached images. Click to enlarge.

The Eduard (Mauve) kit has parts to build up the main gear wells, but only three sides. The upper wing has stiffener detail for the wheel well roof, but doesn't quite cover the whole of the wheel well so I added a thin sheet to cover the gap. This will have to be sanded to allow the fuselage parts to fit, though.

Similarly, the AMT and Hobbycraft (AMT) kits lower wings have three sides of the wheel well moulded on, but not the inner wall. I added some card here too, sitting on a slight slant with a carved out part to clear the wheel well opening, not accurate but close enough. The wings also have stiffener detail, but there is a circular part in the centre where the detail is not as deep, probably an ejection pin point. I left that as is.

I used part of a drop tank (from a Su-57) to extend the fuselage keel into the radiator area for the F and L kits and added a blanking plate in the nose. I'll paint the rear of the radiator on this. There is a bit more work required to extending the angled sides forward with more card.

The assembled nose will look like this, although I also need to add internal detail for the carburettor intake and fair it in at the rear.

This is the AMD P-40N cockpit with an Ultracast seat.

The next two are the AMT F and L cockpits with the seats and cut -down frames from the Airfix P-40C. The seats provided by AMT are the square topped ones that came into production with the P-40N. I have Eduard coloured etch seat belts for these two.

Those are very nice improvements indeed, Michael @michaelt

This pic shows the front of the two Ns.

The Eduard (Mauve) kit had a thick, flat edge to the front of the radiator opening that made the opening rather narrow.

I thinned this down, but that means that the internal divider is now too narrow and there are gaps either side.

I'm thinking about what, if anything , I can do about that.

The prop for this kit is too large in diameter - it should be 35mm scale radius, but the propeller blades are that long. So, I drilled new holes to mount the blades closer to the centre and will reshape them at the blades bas to fit (one done, two to go.)

1 attached image. Click to enlarge.

G'day Spiros (@fiveten),
Good idea, I'll give that a go.
I have some canopy glue, which is really just a thick white glue, that might work.

I have been doing a bit of work on these kits and I only have this long weekend (I don't work Fridays and Monday is a public holiday for the English King's birthday) because they are intended for the Australian Model Expo club display the weekend after.

These are the cockpits: AMT N, Eduard N and the L (the F is similar)