Airbox - cardboard mock up

I made a cardboard mock up of an airbox tonight.  This would seal against the bonnet and be fed by a cone filter somewhere under the bonnet.  Even with this type of airbox it can be seen that the trumpets are quite close to the top which may restrict the air flow into the engine and potentially lose engine power.

It is looking more likely that I will have to cut a hole in the bonnet.