Are you wetting the rope seal prior to installation? The manual does not specifically mention it... but in all the old motors that I (GMC/Ford) have that use leather / natural seals (even asbestos) its is common practice to soak 24+ hours in oil to soften them. At one point a TB was put out that all local spares should be kept in clean motor oil while on the shelf to allow for instant installation.
Its not enough to simply place oil on the surface... gotta let it stew in oil to fully penetrate.
What this does is allows the seal to self lubricate until the motors natural flow of oil would reach it.
What do the seals look like when you remove them? Are the charred? Have uneven wear? If the seals still look new, then its not the seal.
I'd say post pics...
If I remember correctly, Best specifically says to NOT soak the seal before installation. I do believe that you are to oil the surface before installing crank and cap (I think). Regardless, rear the instruction that come with the seal and follow them to the letter and it should work. If not, you have other issues that need to be addressed. I will say that once the new seal is installed, the engine becomes very difficult to rotate. Certainly not by hand.
