Yes its the engine in my Marlin - thanks for the help its a Euro 1750 cc fitted with Solex C40 Carbs !!that the engine in your Marlin?
does the engine number start with.....AR00548 (euro 1750) or AR00551 (usa 1750)..or neither?
you can easily confirm what cc the engine has by the cast mark on the front of the head: if it is a circle with a triangle in it, then it is 1750 first series; identical to that, but with a dot in the triangle, then second series.
https://alfaromeo1750gtv.files.wordpress.com/2013/03/cyl-head-symbols.jpg
Dom