Maybe the pilot bearing is stuck on the input shaft?Clutch hub sticking on the splines?(my best guess) I'd try a prybar on each side between the tranny and bellhousing,and equal pressure on both sides,it'll probably resist,then TWANG-it'll pop loose.Not much you can damage this way...
Speed


1954 GMC 350
1957 GMC 1/2 ton
1962 Chevy C-30
1952 Chevy 6400 dump bed project truck
'98 Harley FLSTC
'66 Pontiac Catalina
'76 Chevy 1 ton Duallie
'84 Bronco II
'78 Dodge W-200
'81 Toyota 4X4 truck