took mine first time about 4 or 5 hours, ripping out the old, and putting in the new.

the other day we did a compression test on my engine, then took off the head, dropped the oil pan, took out the crank rods and pistons so all that was left was the bare block and the tranny...30 min.

All on a lift though with endless amounts off tools and a engine builder/race car driver present. (honda hatchback 10.4 street class modified. Turbo)