There is really nothing to guide the line in on the retrieve since the line will be on the rod and not suspended by the guides. It will probably still cast, but not with much efficiency

Thank you for the input. I didn't think about the snake guides in that respect, so I am canning that idea. I do have an old Zebco spinning rod that I bought for my son when he was a child that I could convert. However, I am hesitant to do that as I believe the guide inserts are plastic and would not hold up well to braided line, and I would have to figure out how to remove the grip. Sounds like I will just try to find a light action casting rod.

A problem you run into with casting rods - rings on top.
From the mid-length to the tip, a casting rod requires more guides. The reason, rings on top put torsion in the rod blank under fish load, and if that strain is concentrated in a small length, the rod breaks. More guides are needed to distribute the torsion over more of the blank length.
Casting rods need more guides in the upper half than spinning rods or fly rods, both of which flex in pure bending without torsion.
These are two nearly identical 8' rods, high-grade progressive finesse taper (Yamaga Blanks TZ Nano spinner and BC III bait), very similar to fly rods,
Spinning on top, casting on bottom, guide spacing in the top 20 inches.
I could do better in the daylight, but this gets the point across.


One way to get around it is spiral wrapped guides (most often used with conventional reels in offshore jigging and surf), which turn the guides to the bottom of the blank and eliminate torsion in the upper half of the rod.

there remains some good discussion on this thread, and worthwhile information.
Making a finesse baitcaster out of a fly rod blank is a good idea.
It will work best starting with a clean sheet of paper and an unfinished blank.

Sorry, I thought I was doing the right thing, but I do see the value to keep it.