The aluminum support beam for the engine room hatch make's it real tough to move about the engine room. My buddy Dexter, who has a 400 down at Spicer's also, showed me how he dealt with this problem last year. I thought it was a great idea, and it was top of my list for winter projects this year.
The aluminum "T" beam is screwed into the 2 x 4 beams at each end of the hatch. By removing those screws and afixing an aluminum plate with a cutout to accept the beam, it is now a very quick job to pull the beam out and gain much better mobility in the engine compartment.
Without the beam in place, it makes it much easier to slide into the port side of the compartment. This picture is looking aft, so the port side is on the right. With the beam in place, there is not a lot of room between the exhaust hose and the beam to slide your body in between.
Here is a closer look at the bracket and the dovetail grinding I put on the ends of the beam to make it all more secure.