I'm thinking about making a custom exhaust header, when I move from the current single downdraft carb to a pair of sidedraft carbs.
On the one hand, since the intake/exhaust gasket has cylinders 2 and 3 siamesed with just one big rectangular hole, my initial assumption is there's no point trying to do long individual header tubes that join down lower.
On the other, when I look through pictures on the site I see stuff like ddgonzal's header that do in fact have two separate header tubes dropping down quite a ways before joining.

So what's the scoop? Is it worth putting a bit of extra metal in the header top to fill in between the two exhaust ports where the gasket is open? Are there gaskets that have a divider there to try to keep the two separate?