Thanks for the help guys.
It seems there must be a major variation in the stud location on holden red six cylinder heads! We took off the holly, and the manifold for the SUs wouldn't go close!
After some hours with a steady hand and some rolling stones we managed to shave a little off the manifold with an angle grinder to enable the bolts heads clearance to screw in, as well as taking a little off the stud recesses and a heap off the little jackets that pull tight on the manifold!
We were't sure where to plug the vacuum advance or how to rig up the cold start, so it was fuel lines in and fingers crossed...
Holding the throttle open by hand (need to make a cable bracket up) while one of the boys held the started motor on and after about 30 seconds of sucking fuel into the lines she started up.
A nice even idle from a cold start, smooth through the rev range and a magnificent sound of 3 SUs sucking in fuel!!!
Big smiles all round
Dave