The only parts on the pump specific to a particular engine are the two midplates which also serve as mounts. From left to right are plates for a small-block Chevy, big-block Chevy, Ford small-block, and Chrysler small-block.
Each of the midplates between the suction stages have a kidney-shaped hole that allows free flow of oil through the stages. This helps even the pressure at all the pickups. Also, only one of the three suction stages has an outlet to the oil tank. This simplifies the plumbing and keeps things light. To handle the extra flow, the outlet is larger than the inlet fittings. As a general guideline, a five-stage pump should pull around 13 inches of vacuum in a small-block racing engine, while a four-stage should pull 10 inches.
Before the completed pan and oil pump are boxed up for shipping, the pan is again checked against the appropriate block to make sure everything fits as it should.
Here's a shot of the oil squirter setup in the valve covers. The oil is pumped through the aluminum tubing and squirts out in a fine spray through the holes near the rail. As you can see from the size of the holes, only a minimal amount of oil is necessary so it doesn't place an excessive demand on the pump or the engine.
Like the oil pan, the valve covers are also checked for fit and finish on a cylinder head.