Always done with throttle open so no vacuum in the intake. All plugs should be out for maximum rotation speed and low load on the starter/battery. If the manifold is off, make extra sure that nothing can drop into the valves. Warm or cold should not matter that much (battery power drops quite a bit when cold). Evenness is the most important factor unless engine is just totally worn out.
compression test, manofold off or on?
dose any one know if performing a compression test results will vary on a la block weather or not the intake manifold is off or on?, the engine is out of the vehicle some what stripped down with the intake off
