Lincoln Mark 8 from 93 to 98 have B heads and teksid block with flat top pistons. I do recommend getting this engine block but not the B heads since C heads flow much better than this.
96 to 98 cobras is the same deal.
99 to 01 cobra have WAP aluminum block with C heads, this would be a much better option because C heads, the WAP block is good for stock hp numbers, if you're planning for over 400 horses I suggest teksid.
Marauders 03 04. They have a 2nd gen WAP alum block with 2nd gen C heads which are revised for better air flow. This is the best option since you can get 305 horses out of this swap all stock.
Mach 1 mustang, they have the exact same engine than marauders except if you find one from a manual trans, if a mach 1 has manual trans the engine has forged crank shaft, if automatic it's all the same thing as a marauder.
Cobra 03 04, well you know this is terminator engine, iron block forged internals and same C heads than any other 03 04 DOHC engine, it also has an Eaton m112 supercharger. If you have cash to spend this is your best option is a direct swap.
Aviator 03 to 05 they have the same large block than the marauder and mach 1, the intake is taller and it won't work with your hood, you will need mustang or marauder intake.
99 to 2002 Lincoln continental they have the same C heads than 99_01 cobras, they also have a teksid block but this one is useless since the bolt pattern in the trans is differe to acomodate a front wheel drive trans. They are easy to come by in junk yards..
And for last but not least the Navigators, a 5.4 DOHC engine with C heads. The C heads are not the same as the rest because has bigger ports due to 5.4 stroke, very few mustang guys have swapped this whole engine in Mustangs. This is probably the least desired swap since it involves a lot of work to make it fit.
Just your luck, there is a marauder at the LKQ IN North ave, engine still there. Also there's an aviator at the victory yard in Bensenville.