The bike is basically a 1960 Matchless G2 fitted with the larger 350 engine from a 1961 AJS model 8. It also benefits from the better teledraulic forks. I understand that the only difference to these two AMC bikes was the colour scheme and the tank badges. The engines were, either 250 or 350. Both engines were virtually identical the extra capacity of the 350 coming from a longer stroke.
Matchless Model G5
1962 Matchless G5