When the engine position is a problem, some hotrodders use the tub section of a wheelbarrow to move the middle of the firewall back. It's stamped out of good-quality steel, and all the compound curves are already there. Just trim it to fit and MIG weld it into position.
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!