Thanks for the advice ,but the plan is to go with the original drivers as the box is tuned to their specs .
A long time ago I had one of the staff at scanspeak ( they imported mostly Scandinavian
driver and speaker kits re calculate the port length for the long throw drivers.
The original kit was published in Electronics Australia in 1987
If I cannot get Whole drivers I'll try and find somewhere I can get the voice coils re wound
I may get lucky . haha.
There were a pair for sale in the U.S.A but including shipping the cost was ri