I’ve done this job on my GMC 270. In my honest opinion it’s best to lower crank even from front to rear. I removed the radiator, crank pulley, dropped torque tube, and removed the transmission. Then it’s very easy to lower crank and remove the rear main seal. I also used the best gasket brand rope seal. Pack as much of it as possible in the block side to make sure it’s fat in the block, to make as much contact with the crank shaft surface as possible. Same on the bearing cap side. I used RTV lightly on both the bearing cap and block surface. I snugged it down tight. I let it sit overnight and then raised the crank back up the next day, torqued the caps and then put it all back together. Little to no leaks.
