I did a double-take when I saw this photo! The bike is a Monark sourced JCH to a design I had not seen before. The earlier Monark/JCH bikes are generally familiar and turn up fairly often in the early fifties exhaust manifold decal variation. This bike is apparently a later version specially produced to add the under-tank fins to the bike. The tank itself is the standard Monark Rocket tank, not the Murray unit, but to fit the fins the frame was modified with a front drop added to the under-tank bar. This drop brings the frame in line with the deluxe tanked Monarks of the period except it is different, The monark version has an under-tank bar with a different curve than what was required to facilitate this build. Altogether a unique variation that leads me to wonder how many of these frames were made and how many have frustrated would-be restorers when it came time to find a tank. The addition of the JCH/Murray-Ohio springer probably never happened on the originals being from separate factories. If they had produced a springer one wonders if they would have used a Monark unit?
here is the one I used to have, I added the fork it originally had the same fork on yours