Hi Converse,
You want to talk buses, I'm the guy. Those MANs you mentioned were the MAN SL200 mark 1 and 2. The Mark 1 had the ugly looking older style body and the mark 2s had the square looking more modern shape and higher horse power engines.
Sydney had hundreds of Mercedes Benz 0305 city buses and I have learned they are basically the same bus chassis and mechanicals but with their own engine ancillaries and different transmission choices.
Other than that, they are very similar underneath.
The Volvo you describe would be the Volvo B59 rear engine bus with the massive destination screen up top.
They had a very advanced (for the time) 9.6 litre turbo charged engine (the MANs were 11.4l NA) let down by a dated 2 speed ZF automatic and talk axle ratio.
I actually rode one with a private operator in Sydney bought second hand from Melbourne and was shocked at how slow these things were from the mark. They later fitted three speed autos to them which made them much more acceptable but still slow due to the tall diffs in them.
I have a 1:76 scale model of a M&MTB Leyland National bus which Melbourne took delivery of 30 units in 1975 and were run until about 1990 when they were retired and sold off to other operators or scrapped.
You probably rode them as well at some point.
Just Google image search Leyland National and you should recognise it. They were once a ubiquitous sight in the UK and some have been preserved and restored there.
