I made the original patterns for the head & crankcase , and the problem wasn't the Australian ally foundries, it was, at the time cheaper to have them cast at the local aluminium balustrade place around the corner ,( at my vocalised disapproval ) .
they stuffed the head pattern , and their quality and ability to melt aluminium , well , that's it really ,
and at about the same time CNCwas coming to a place near you .
so ian bent got involved .
also at the time rod wanted to keep all the work & contracts local .
and at that time ,for casting heads & crank cases , you needed aluminium patterns and shell moulding technique
all of which were available in Melbourne , at a price$$$$$.00
cheers mike