Firedome . . .
Leaks really aren't much of a problem in a properly maintained car, particularly one using the LHM mineral fluid that replaced brake fluid for '67 (or mid '69 for North American spec cars). LHM doesn't absorb water and provides good lubrication for the system. Most leaks will occur on the low-pressure return side and are a result of old or worn out rubber parts that are available and not bad to replace. One nice thing about D and SM cars is that there are no rubber bushings in the suspension, everything pivots on tapered roller bearings so unless the car has freakishly high mileage all it takes is a system flush and new suspension spheres to make it ride and handle like new. The spheres just screw onto the hydraulic struts; compare that to my modern VW which can't go 40,000 miles without needing replacement of rubber bushings that required disassembly of the front suspension.
The SM's Maserati C-114 V-6 is a neat little engine, very compact and lightweight. However, unlike the old Citroen built D series inline fours, which are as tough and reliable as most anvils, the C-114 has little tolerance for lack of maintenance and absolutely none for improper maintenance. If all four camshafts are timed correctly, the left and right bank ignition points are synchronized, and each of the three carburettors are synchronized both to each other and left barrel to right barrel, then it's a little sweetheart with a surprisingly even torque curve and more oomph than you might think -135 mph for an early '70s luxury car was pretty damned good for 2.7 or 3 liters. If everything isn't perfect then it becomes a little bit spastic and betrays its uneven firing design - the crank rotates 90 degrees, one cylinder fires, then it rotates 150 degrees, another fires, then back to 90 degrees and so on. In fairness to Maserati (and Guilio Alfieri, their very experienced chief engineer during those years), they were a tiny company and simply didn't have the resources to worry about owners who didn't maintain their cars.
