I have a 186, and bought an aussie 4 speed to fit to it. The 4 speed came with a flywheel, clutch disc, and pressure plate
I installed my old flywheel that has always been on my 186, and then found that the pressure plate was larger than my original. The clutch disc was also of larger diameter.
I decided that the significantly larger clutch surface area might be a good thing, so I then installed the flywheel that came with the 4 speed, along with the matching clutch gear.