Great to have the website up and running again.
John we had several 4840's around here in Lincolnshire on the larger arable farms, one local farm had two one with the Caterpillar engine and the other a Cummins, you certainly could tell the difference between the two.
So if this tractor has a Cummins in it you NEED it in your collection!!! maybe you could persuade the Company to sponsor the purchase and help the preservation of agricultural history??? Then you will need an extension on your shed, it just never ends.