Amal Carburettor not only has some high quality images of the Mk1 600 and 900 series carbs that are found on the MG products, but they have rebuild kits and a very comprehensive list of available replacement parts for these old gems. Replacement bodies, replacement slides, springs, gaskets, screws, needle valves, the works - but what blew me away is the fact that you can order BRAND NEW Mark 1 Concentric Carbs directly from Amal, with your choice of bore - and other than having improved on a number of the component parts over the years, these are visually and functionally identical to the classic originals.
Amal MK 1 - left hand alignment. Photo courtesy of Amal Carburetters.
Amal MK 1 - exploded view. Photo courtesy of Amal Carburetters.