Without being certain, I'm guessing this is the type of CAV pump you have. Fairly simple to remove. There's a round timing gear cover plate on front of engine, remove that cover plate to access timing gear retainer bolt #24 and remove bolt. At this point, note which hole in timing gear that dowel pin #23 is located in, mark that hole position with paint stick or something similar.
Remove all fuel line connections. In some cases, pump can be removed while leaving injection lines still fitted to engine clamps, but in most cases they interfere with pump removal and therefore require removing injection line vibration clamps and removal from injectors, then injection lines can either be pulled out of the way or removed entirely. Also, I think this vintage engine used a gravity flow fuel supply, be sure and turn off fuel supply to prevent supply line flow.
Lastly, the pump is fitted to engine with three bolts #20 going into slotted holes in pump housing. Very important, prior to removal of bolts, make a punch mark on edge of slotted hole seen in illustration, then a matching alignment punch mark on plate that pump is fitted to. That way you can re-install pump in exact location it was in prior to removal.
Once you remove the three mounting bolts #20, pull pump from mounting. It may require screwing bolt #24 back into pump shaft a few threads and give head of bolt 24 a rap with a hammer to pop pump shaft loose from timing gear.