low oil pressure or the seal on the roller tappet is old and it takes the roller tappet a minute to pressurize again.
I would not worry to much about this noise when the motor is cold; engines have clearanaces that come together at operating temperature. If this noise happens when the motor is at operating temperature then you might have a problem.
It sure can.
Rods and Rocker arms were the problem with my Malibu after changing lifters
The most common cause of lifters knocking is low oil pressure.
Exhaust leaks, bent pushrod
Could be, Out of adjustment Worn camshaft Worn lifters Worn pushrods Worn rockers All of the above.
It sure could. If you KNOW how to use it and READ it.
it will cause the engine to overheat and also coolant to enter the oil system, which will in turn cause wear of the lifters.
A bad fuel injector poppet could cause that.
Not if the are the same fitting wise and gaskets are used if necessary. There could be differences as the vortec is designed differently.
low oil pressure could be one cause cold oil is heavier in viscoity and as it warms it gets thinner, the lifters are not getting the oil inside of them causing them to colaspe try having a new oil pump installed