Yes it can - now you might have to loosen all the main cap bolts to let the crank drop a smidge but it can be done and you will have to rotate the crank to help pull it in.HI wakjob, all I can say is that your Manual isn't correct on that statement. I and many many others have done it many times over years with both the rope and neoprene type seals as an example I did my first one like that in the mid 1960's. They can be installed with the engine still bolted in the chassis and without compleatly removing the crankshaft there is even a special tool made to remove and install the rope seals and the neoprene seal can also be very easy. Best of luck