UncleKes,

The topic is line for casting distance, not rod length.
In all simplicity it's rod length, but there's no way a 7 foot rod with stainless steel guides will outcast a 6 foot rod with Fuji SiC guides, if all other things equal. Common sense has nothing to do with that, because common sense doesn't measure the friction properties of each material nor the kinetic momentum transferrence of rod type nor the threshold of the line slap cone from the reel to the first line guide in spinning rods. If your rod tip vibrates on a cast that's going to degrade your casting distance. Again a 6' rod like a St.Croix LE will outcast a 7' Shakespeare Ugly stick. A rod that has a small first line guide ring placed close to the reel matched with a big spool reel will mean that there's so much more line rub from the sharp angle resulting in degrading the casting distance. The concept is line performance.

Don't be sold by the simple idea of larger spool means more casting distance. It has an optimal performance threshold. Small spools have big change in spooled line size as line unwinds and the angle of line to lip increases contact angle. Small spools have advantage of smaller initial inertia to unwind line.

A 5'6" foot casting rod with a pistol grip handle measures almost the same as a 6 foot casting rod with a standard trigger grip handle being measured from the reel seat to the tip of the rod. There's maybe only about three or four inches difference, not an entire six inches difference.

Now this is where user and equipment design becomes more of an influence. If your reel is kindof low budget it's not going to help you as much as a better reel with better line management. Line management on the spool is affected by the tension and the wrap pattern. Do not expect that two reels of the same size where one costs fifty dollars will cast like one that costs five hundred dollars. Don't let your common sense fool yourself on this.

Lines. Supple low friction line will outcast stiff abrasive lines. Don't kid yourself that the light line will always be better. Light line are more prone to wind knots as well as bird nests or just plain old twist and kink on you. The less test# your line is the more prone it will break on you. Longer rods have more leverage and that means you will need a stronger line test# to handle that. Even line properties like the stretch factor of mono line over that of superline will play into the shock absorption of it. Just like casting can put immediate tension greater than line test#, the method of casting needs to adjust accordingly, especially when using live bait. Your bait just went solo...

It's the whole combo...plus user and budget...And not as complicated as I make it sound.

I read from BASS: Amongst bass pro anglers, rod length as a consideration for casting distance is the least importance. Most of them can cast with very near equal distance between a 5'6" and 7' baitcasting rod. It's the presentation technique and need to leverage a hooked fish.