 The heads for 175CD Zenith-Stromberg carburettor had two siamesed stubs (part of the head casting), making them not interchangeable with earlier heads using Dell'Orto DHLA40 or 40DCOE Weber carburetors, whose intake was four individual tubes (also part of the head casting).Exhaust gases were handled either by a cast-iron manifold or a fabricated tubular header, depending on application.The original in-block camshaft was retained and, as in the original 116E, drove the side-mounted distributor and nearby external oil pump/filter assembly, minimizing modifications to the mass-produced iron block.