Are you using the bellhousing with the rear mounts at about a 45 degree angle to the crossmember? Those mounts are pretty thick, which should establish the right angle for the crankshaft. The same cast iron bellhousing was used for both 6 cylinder and V8 truck engines in 63. The aluminum passenger car housing won't work without fabricating mounts for both the engine and transmission.
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!