How do you know where to place the carburetor? Is everyone just putting the secondaries flush to the back wall... and doesn't know if it's a mistake? ...
Good question, at least the part dealing with an ideal position. For my part I am primiarly driven by the existing mounting pad locations...so as you can see in the photos the carb studs or bolts will center the gasket and that means I would be attempting to match the shape of that gasket.
Yes, there is a bit of play there, but it's not much...however, if one was to say "move as far forward as possible", well, that would mean I probably have about 0.050" movement to the front that the current mounting will allow for and therefore I would be aiming to optimize that location.
