For mocking up engine swaps, I usually use a bare engine block and an empty transmission case for establishing the location of motor mounts, crossmembers, etc. Even with a set of heads attached with a couple of bolts to check firewall clearance, etc., it's a lot easier to maneuver than a complete assembly.
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!