24mm open wrench at the back ot the shaft to hold it and use whatever size wrench for the bolt. you have to take off all bolts holding the head down. if you decide to take off the intake manifold, take off all bolts holding it to head. there are a few bolts holding the intake to the block, take those off so you can pull the manifold from the head (you need a little play to clear the studs). NOTE: there is a hex bolt by the cold start injector. there is a matching bolt on the same vertical line right below the intake manifold.

Dont force anything off with crowbar! a hard tug usually is all you need. if it doesnt come off increase strength accordingly after ascertaining no bolt is holding the part down.

Before putting things together dont forget the torque specs on all bolts.