This is a common problem when cold on these Chevy engines. As long as the motor comes out of it as it reaches operating temperature, I would not throw dollar bills at it.
Not sure what engine you are working on but sometimes you can roll the engine backward and get the gear to disengauge .
No, it will not. Low oil & or pressure will not prevent the engine from starting.
There is no ideal pressure. Of course the oil pressure will be higher when the engine is cold. After it is running and at full operating temp, the pressure should read at least 10 lbs while idling. The pressure will be directly related to how many miles are on the engine and the amount of wear. A new engine will have around 40 lbs when hot and running at 2,000 rpms, and around 30 lbs at idle.
the fuel pressure is around 30psi
Yes, that is possible. Never overfill any engine.
After starting the engine, the oil pressure rises. The switch changes from either open or closed at a predetermined oil pressure, switching off the warning light. If oil pressure drops during operation, this light should come on, warning you of this dangerous situation for the engine (and your wallet).
Engine oil pressure will vary depending on if the vehicle is in an idle state or not. However, on average, it should be around 40, which is typically half of the gauge.
Could be the TDC Sensor, sometimes called the crankshaft Sensor.
Worn main bearings sometimes knock when cold starting
Did you change the fuel filter? Have you checked the fuel pressure regulator?
It means that the oil pressure switch is showing low pressure.
the pressure in the engine will stop it from starting (oh 305's are shite)