WOW, that adjuster looks short for a 273 rocker arm. Most competitive stuff has moved away from aluminum rockers for many reasons. Bulk is one of them.
Again, that adjuster looks SHORT.
I'd call Smith brothers and see what their adjusters cost. Think about this for a bit and see if it starts to get clear, and I'm not trying to be an ***, I just want to grease the wheels about mass production parts.
For the same reason that Chrysler used a relatively short installed height on their valve springs is the same reason why manufacturers use the shortest fastener possible....it costs less.
In the case of valve springs, you need 16 per engine, times the number of units and you can see the cost savings when you consider the total number of small blocks built was in the millions. In a smaller way the same thing happens with other products.
That adjuster is too damn short.
Unless pictures make things look shorter!!!!