here: viewtopic.php?f=1&t=15421&p=70577#p70577I actually don't care that much for the 408. Every part is the same as a 308 except for the main gear and pinion, and it's blue colored instead of black. You get a slightly higher gear ratio and finer helical gearing that is more prone to getting damaged.
At the time I had never cracked open any of my flock of Mitchell reels, but I wondered how could it be that Mitchell didn't change internal parts for those reels over that time frame? I've been going through my ULs trying to get them all taken apart & serviced recently. Since I had never taken a Mitchell apart I did a search and didn't find any internal pictures here for either model for a comparison. So, since I have both, a '62ish 308 #394051 & a '65 ish 408 #1008313, which are quite a few reels apart, I figured I'd post a couple of photos showing the how the parts compare side-by-side for future reference. Smead was right on the money with the internal mechanical parts reference. The only real difference inside is the faster helical gearing, all the other internal parts are interchangeable.
Externally, mine have a couple of differences. Because it is such an early model, my 308 has the spring loaded handle, the 408 has the threaded locking style. The bails are a little different, also. They both have the same type line guide but the 308 bail does not rest on the bail trip lever like the 408 does. The 308 has a small protrusion on the inside of the bail plate that rests on the square top of the bail spring housing. Both rotors have the same square top bail spring housing, so, the bails are interchangeable.
Here are the internal parts side-by-side. All of the parts on the left are from the 308. The 408 parts are on the right.
Here is an enlargement of the main and pinion gears. The 408 high speed helical gears are on the right. Also, if you look closely, they reversed the "Made in France" and Patent #s from the 308 to the 408, but the Patent # is the same on both rotors.
Side-by-side, 308 left/408 right. You can see how the 408 bail plate rests on the bail trip lever and the 308's does not.