Recently spent 2 days removing top half of a leaky rope seal in Y block in our 55 T Bird. Installed a neoprene seal, no more leak 'yet' anyway. Was faced with pulling engine until devising a rather homegrown Bubba solution that got it out. Sneaky Pete tool to remove proved worthless.

I do not believe that is recommended to install a rope seal unless crankshaft is removed from engine. These Sneaky Pete solutions to pull a new top half in with crank installed at prove problematic at best. They can stretch the new seal and oft times you will find that seal is not properly seated in block and will leak.

Advice as suggested earlier, try a neoprene seal first.