High quality exhaust valves manufactured by G & S Valves - Following Head Sizes available (check your original) : 1.735" or 1.750". Standard Model 30\40
stem diameter : 3/8" - Stem length: 4.635" or 4.650" - both these being a common longer length valve (see also 0037B for slightly shorter exhaust valves of the same head diameter). Note - only 15 thou difference between length of stem of these valve variants - so if corresponding inlet valve length is not available, but other size is - 15 thou is easily adjusted for with the rocker 3 part adjuster.
These valves already have the collet groove machined and are ready to fit. Note: Norton cammy valves were made in a variety of lengths over the years, although not as commonly used as the shorter lengths, both these lengths - 4.635" and 4.650" were sometimes used, particularly with larger inlet valve heads. If you have an original then measure that. If you are unsure please email me.