I have a friend who's trying to restore a 60's vintage 289 Mustang. Apparently, the motor was rebuilt and turned over easily when it was parked . . . about 10-15 years ago. Not surprisingly, it is now an immobile lump that won't turn over even with a breaker bar on the crank pully. Any miracle cures that don't involve a complete tear down and rebuild? (I'm not thinking of any, but since you guys routinely come up with miracle cures for seemingly impossible problems, thought I'd give you a shot at this one)
And remember, its for a good cause (1st gen Mustang) 
Kerosene or Mystery Oil in the cylinders, let it soak for 24 hrs.
I have even heard the Coca Cola will work.
In reply to kazoospec:
I have successfully gotten an engine to turn loose by spraying a lot of penetrating oil into all the cylinders for several days. Also, remove the valve covers, and spray penetrating oil onto the valve stems. Lightly tap the top of the valve stems of especially the ones that are open to make sure they don't stick and get struck by the piston. After you're sure everything is free, use compressed air to blow the oil out of the cylinders and put a little engine oil in them and turn it over a few times with a bar. They it should be safe to start. I've done this several times. I've also tried it on a few hopeless cases.
http://www.kanolabs.com/
kroil is good stuff
How about soaking the cylinders as mentioned, and then using compressed air in the cylinder that is closest to TDC? Plus the breaker bar maybe.
ATF should work very nicely.
From what I understand, he's tried a WD40 soak, to no avail. Any thoughts on trying the GRM magical mystery sauce (50/50 acetone & ATF)?
WD40 is not Mystery Oil, not even close.
kazoospec wrote:
Any thoughts on trying the GRM magical mystery sauce (50/50 acetone & ATF)?
AKA "Weasel Piss" Good stuff! 
I got a stuck Toyota four unstuck with a 48 hour kerosene soak....ran another 100,000 miles after that.
Toyman and I freed up a stuck SBF with a bunch of PB Blaster in each plug hole, then soaking the stuck open valves and banging on them with a brass drift.
Photo evidence:
Grandpa used to always pour some Rislone in the cylinders of any farm equipment that was getting parked for the winter, and I have used it to condition rings/free up stuck pistons on several engines, in all sorts of poor condition, from Briggs, Pontiac, Volvos, to Continental diesels.
