Should be a 1953 Powerglide 235, the first stovebolt with full pressure lubrication an aluminum pistons.
[From the Stovebolt links.] You have the correct valve and side cover. Does it have the oil distributor plate on the block below the center intake port? The full pressure engines do not have this plate.
{Also from the Stovebolt links.] This illustration says "1953-1957,,,typical", but only the 1953 standard transmission engines used the oil distributor.
Hope that this helps.