Some of the race cars I've built use a 1/4" thick aluminum plate between the block and the bellhousing with engine mounts adapted to it. It's necessary to use a longer pilot bushing on standard shift applications or use 1/4" thick washers between the flex plate and the torque converter on automatic transmission cars to use that setup.
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!