Use a piece of the tub from an inexpensive stamped steel wheelbarrow to modify the firewall, and don't get involved in relocating the bellhousing. It's a quick, simple way to create some clearance at the rear of the engine, and it doesn't seriously compromise foot room inside the cab.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!