That is not the pump, J_J. This one is really old, as is the whole splitter. It is a home made splitter that I got from my son who got it from a friend, who got it from....well, I think it may go on for a few more. It's a rat nest of plumbing, as it has two controls. The one with the lever (Geeess..I need to take a pic of this!) that operates the cylinder is controlled by the lower one that kicks the system off, unless it's button is pressed by a tab on the cylinder shaft. There are so many 1/2" and 1/4" lines on this, it's hard to tell what's going on. The end of the cylinder is bolted to a large, 4" thick steel block filled with ports and cavities. The plan is to salvage the engine, cylinder and pump, add a new and up-to-date valve control and have a 'proper' log splitter.
I will put a new gauge on to check, as the existing is broken.
All the controls and relief mechanism are Sperry/Vickers.