Prep work

Before you start on the cowl, there are a few things (obvious?) that need to be done.

The engine must be hung and torqued up. Any changes to mounting may cause cowl to not line up with prop spinner.

The flywheel, prop exentsion and rear spinner bulkhead must be installed. The rear spinner bulkhead acts as a positiong reference. The prop should probably be on, as the weight of the prop will cause the engine to sag a bit more than with it off. You will want the engine generally in the final position so you can get the appropriate gap between cowl and spinner.