It sounds like you clutch pressure plate might have broken. The return tension on the pressure plate should be enough to get your pedal to lift back up off the floor.
Is all the clutch linkage under the car still intact? The bottom springs are just there to keep the lower pushrod in constant contact with the clutch fork. If thos little springs have rusted away, you could have just had the linkage fall out of place.
Your Z-bar is supposed to ride on two nylon bushings. I think the V8 cars had a ball style bushing and the 6cyl cars had a sleeve bushing. They are somewhat interchangable, so you might find either (if they are still intact). When these wear out, your Z-bar will have extra play and could cause the upper pushrod to be off center.
Also make sure the bushing on the clutch pedal is still there.
04 SVT Cobra, Torch Red (daily driver)
67 'vert 302,4spd,Red/Red (almost ready!)
67 Coupe 289,auto,black/black,deluxe (sold)
67 Coupe I6 to V8 conversion (sold)