Just an FYI.........I just finished a rebuild on my port engine......Engine was running well when Bang! and the engine seized. The other poster is correct. If it's lower end, the engine will HAVE to be pulled! You can't even get the pan off any other way. Once we got the engine out, I sent it to a perkins rebuild place north of Houston. Getting the engine out and then reinstalling was actually more than the rebuild. Part of that was finding worn peripheral parts, IE: raw water pump, motor mounts, etc etc etc.......but believe me, on my Mainship, getting the engine up from the engine room then out the sliding door is NO EASY TASK. Most external parts had to be removed. The ultimate cause was the rod cap fell off and the rod went through the block. OUCH! Is yours seized?
I have posts here of the pics of removal and reinstall of the engine if you can find them.