Motor mounts, fasten to block OR frame first?

[anoblefox]

Will be dropping engine in soon, have always mounted motor mounts in the frame (5 times now) before installing engine. Does anyone have experience bolting them to the engine first, then installing engine? Is this something worth doing? The trans is a C4 and already in place if that makes any difference. Also, is there any chance the shorty headers could remain on the engine prior to the engine install?

 

[Broncobowsher]

In theory, block first. For a frame off I am sure that works perfect. The adjustment slots are on the frame side, the motor side has nearly no adjustment to it.

Reality, I leave them off until the engine is in place. Wiggle them in and bolt them to the engine. Weight in the chassis and the engine level side to side. Now nuts to the frame.