Jeff, head casting # 3701887 is an 18-bolt 235 head, not a 216 head. It is interchangeable to the '54 and later 235 heads, so compatible with your F54Y engine/block.
By coincidence, I have a '53 235 in my shop at the moment that I picked up as a rebuildable core - engine number prefix LAQ - from a Powerglide car (which was the first of the "full pressure" 235s, with insert rod bearings, as used in the '54 and later 235s). And it has the 3701887 head, original to the '53 "full pressure" engine.
A few photos of the numbers, just FYI. First shows the head casting # 3701887. Second photo shows the head casting date code (valve cover removed to see it) - very late '52 casting for the '53 model year. Third photo shows the block casting # 3701481, and the fourth the block casting date code - again very late '52. Last photo is just an overall of the engine as it was pulled from the '53 Bel Air (the Powerglide transmission and torque tube rear axle assembly from the same car are in the background).
