This is a compact pump, but the darn thing has four pipes leading to and from it. Lots of plumbing.
This model was used on the 283, 327 and the 430 and 431 Lincoln motors. Check specific model identification on the drive side of the pump, see pic
Here's what the other side of the pump looks like, note the crazy 4-port design.
General view of the pump
Pop that front case off and here's what is inside. Front case needs to be gently persuaded off so as to not scratch up the mating surfaces of brass or the gasket.
The front impeller comes out pretty easily, note the drive key and also note there is a flat plate inside the pump that now has to be removed. Note also the cam on the bottom side of the internal pump chamber.
(see next post for more photos)