Think about it some more, and how much you really want to do.
Engine swaps are only for 0.1% of the population because many of us find it very frustrating. So relax a little, and do some planning.
A 2300 and 2800 are basically Cologne designed engines which use the same mounting points at the frame. The V8, OHC 2.3 and 2.8 V6 use the same cradle so it may be easier to go 2.8/2.9/4.0 V6 or 5.0 V8 for an engine swap than an I6 3.3 cradle swap.
The I6 has a totally different pressed stel 'pods' welded on to the cradle, so its requires you to lower the cradle out under your Stang, and then replace it with a 80-83 I6 3.3 one from any Cougar, Tbird, Fairmont, Mustang or Capri. It's a straight swaps right in though.
Don't rush things.
A good 2.8, 2.9, 4.0 Cologne V6 would make the car a delight. The engine in German form the 2.8 had 160 hp in the 1978 Mechanical Fuel Injection version, good enough for a 15.9 second quarter mile and 130 mph while still getting fuel figures in the high 20's with a 4-speed manual gearbox.
Stock truck 4.0's bolt in using the later Mustang SN95 engine mounts. You could even wack in a 200 hp ExplorerSOHC or Mustang SOHC V6 and you can put in a 4 or even 5 speed auto gearbox from the Explorer into one, or just use your stock C3 or C4 gearbox.
Or you can go 5.0.
There is no limit to what you can do.
I'd look at the 4.0. It puts out 165 hp in stock form, and is a really strong American build tall deck version of your existing 2.8, with EFI and a great exhast system. Later SN95 stuff fits too. Sump is the same, the basic block has the same hard dimensions, its just 0.76" taller in the block with much better heads, a perfect EFI and ignition system, and is competenty engineered.
With people wanting to ditch SUV's, a 4.0 Cologne V6 is a good option. Only thing is, it has very specific sensors and parts which make it important to read the shop manauls. Things like cam swaps and header kits are very complicated for this engine because it's specifically a Mustang or Explorer engine, and you have to know the year and modle of the bits. Many extreamly good aftermarket kits abound for the engine, but you gotta know to undestand!
The I6 is a super simple six which is very user friendly, and any problem can be fixed without too much fuss.
Think it over!
changing from an underpowered engine to just a tiny bit less underpowered engine won´t be worth the try.. stick with the current one.
