Per the 1957 Service Manual, “Oil Pressure (psi) Hot @ 2000 rpm – 45-50”.

Here’s a link to an older thread regarding pressurizing the oil shafts along with other oil modifications.
http://forums.y-blocksforever.com/FindPost10464.aspx

Lorena, Texas (South of Waco)

I've not read any comments regarding an increase in overall oil pressure when pressurizing the rocker arms. However, a general rule of thumb (not limited yo Y-blocks) is 10 psi per 1,000 rpm. Keep in mind that a cold engine will be idling at a higher rpm, and the oil viscosity will be greater, so you'll have higher oil pressure until the engine reaches the normal operating temperature and idle the idle speed is normal (choke is off). 

Does this modification affect oil pressure?  What is considered standard oil pressure for a stock 292 (1955 Thunderbird)?