I have two of these engines. They seem kinda hard to come by.  They are neat little engines, 80 horsepower from only 2 litre displacement.  They were used in automotive applications in Europe.  One (pictured) is complete minus the injection pump.  The other is a short block, wrapped in plastic, condition unknown.  When time permits, I will unwrap it and inspect the condition.  It could be a fresh rebuilt short block.  If interested, give us a call.  Here is a little information on the Perkins 500 Series:

Produced as a Joint venture between Perkins, UK government and the then Austin Rover Group. Based on the “O-Series engine” Austin Rover O series

engine this engine had major parts produced at Longbridge by Austin Rover with final assembly by Perkins. It was entirely designed by Perkins who also sold it to external customers. It was used by Austin Rover in the Austin Maestro and by LDV Limited in their 2.5-tonne van.