The friction surface of flywheel was full of thermal stress hair cracks and discolored areas from overheating. Workshop manual indicate that machining is allowed provided that the distance between the friction surface and the surface that pressure plate is attached remains unchanged or between some limits which was followed. To my opinion the bead blasting was not needed because increased the friction of the surface that clutch disk is touching thus need to break-in and become less abrasive. At least this is the only explanation that I can give... I will try to break-in the clutch set with some intermittent slipping on the flywheel and see if my assumption is correct.
thermal stress cracks on the flywheel surface means only one thing:
New flywheel time.
Did you replace the T.O. bearing?
Did you make any inspection of the input shaft where the clutch disc should travel freely?
You said “1975” GTV. Is this the Alfetta ?
I remember one case of “over resurfacing “
where a spacer was needed between the flywheel and crankshaft to bring flywheel closer to “clutch release zone”.
A spacer on the T.O. bearing would work too.