Those are meant for American pushrod V8's where the camshaft is located in the V between the banks of cylinders and the center distance between the crank and cam is not too great. In order to make it all the way to an overhead cam, you need an awful lot of gears.
It can (and has) been done. Various Honda motorcycle engines have gear driven cams, most notably later model VFR750 and VFR800, and the RC45. The whine of the cam drive train is clearly audible.
Brian P.
'96 Passat TDI
