To add a little to CJ's scenario.
The pumps are notorious for binding up if the body and nose are twisted, which will happen if the thickness of the pump gasket and fibre washer under the front stud are different when tightened down, as outlined by CJ.
The A65 type one piece gasket overcomes this foible, but must be cut down slightly as the A65 pump nose is longer. The oil ways and fixing studs for the body match. There are some abysmal pump gaskets included in gasket kits, some so poor as to obstruct the oilways.... A quality one is well worth it as it really does sit at the crossroads of the flow and scavenge systems and failure here has been shown to cause all sorts of mysterious mis-behaviour.
Swarfy.
