Thanks Scott for carrying the torch. I tried for some time to coax people out of using ?Zep? to describe all the similar frames Snyder produced under various badges. Unfortunately there does not seem to be a single factory name for this ubiquitous frame. I tried the ?Snyder Fastback Sport Frame? but that has yet to catch on. (LOL)
Montgomery Ward used the Zep name for their top of the line bike for years and on many very different models. The 1937 version which uses the ?Snyder Fastback Sport Frame? is unique in the Zep version for the inclusion of a built in head or fork crown lock which separates it from the lesser Hawthorne Comet and Sport models also built on a version of the ?SFSF? frame.
Anyway, I?ve generally moved on to beating other dead dogs. In the hobby, if you want to verbally conjure an accurate image of an SFSF frame in someone?s mind there is no better way than to call it a ?Zep? style frame.
The frame in question was the backbone of Snyder production between late 1935 and 1938 and remained in production perhaps into 1940. There are lots of small variations in the frames due to production modifications over the production span.
Snyder serial numbers are confusing and not entirely helpful for dating a frame but your Zenith has the locking collet seat binder which was adopted in 1936 and dropped for 1937. The earliest 1936 style frames have closely spaced top tubes and will not accept the tank. Your frame looks like it has the larger aperture so it is probably from mid to late 1936.
This link is to a Snyder built Marshall Wells Zenith bike that Shane has. It is the Moto-Balloon model which is probably a bit earlier than your bike but the two styles were produced concurrently for a couple of years.
http://www.thecabe.com/vbulletin/showthread.php?t=7282&highlight=zenith
Snyder had a short pallet of colors on general, standard offer at that time and Cobalt blue seems to be the default color for a lot of the Snyder production with Indian red following a close second and Black third. Maroon, Green and Suntone (Tan) also were available in the Snyder spectrum. It looks like some blue is showing through beneath the black on your bike. The plain white darts are likely the pattern that was original to your bike. For the rest of the bits that would finish the bike I would look at what was standard Snyder fare in 1936 (painted full crescent fenders,etc)