There are light flywheel options off the shelf for the A series. Since tilton are no longer making the alloy units, I believe the pattern is being replicated or at least very similar. I bought mine new last year to take the factory style pressure plate, but the manufacturier will gladly fit any of the tilton race options to your requirement. From memory it was about $350 delivered to sydney Aus.

The advantage of an alloy unit with a chrome Molly insert is that it has superior thermal dissipation properties and that the ring gear is based on the factory offering and is replaceable .

Flywheel only $500 ono.
With Tilton racing clutch $750 ono.
Replacement cost (new) about $1700 for both.