Can,t help with grafiics. Visulize your motor mount bolted to the firewall as intended but now you used longer bolts throught the mount and firewall and you placed four tubes or a drilled block of wood between the mount and the firewall the thickness of these 'standoffs' is the distance you want to extend the motor forward. The long bolts pass through the motor mount then the tubes or block of wood and finally the firewall.

John