[Luddite]

Originally Posted by Mr Gazza

I bought one of these and it won't even pull the skin off a rice pudding!!

https://www.ebay.co.uk/itm/Powerful-...0AAOSw0vBUiiCI

What numbers do I need to look for to get something that will get my clutch nut off?

Clutch nuts are in the region of 190Nm so that one you bought (310Nm) should have done the job. As it's an air wrench, could your compressor be the limiting factor?

That corded Clarke one I mentioned above is rated at 450Nm so should be more than up to the job.