Hi all. I know I asked a similar question to this a few months ago asking about changing the rear crank seal on a sbc whilst the engine is in situ. To be honest I haven't gotten round to changing it yet hence the new enquiry. When changing these seals do they have to be replaced like for like, i.e original rope type for the same or can the rope type be replaced with a newer neoprene or rubberised type? sry, not sure of what they're made of.