I've got a question for you about the seal surface on your crank: is it smooth or does it have diagonal grooves in it across the part that rides on the rope seal?
If it has grooves, you may have to use a rope seal. The rubber seals will get the lip ground off very quickly if it's not designed for the grooves. If the surface is smooth, then you can use either type of seal.
Keep in mind that your rubber seal can rotate in the groove, just like a spun bearing, and open up on one side or the other. The seals rely on friction to keep still against the crank trying to rotate them. What may be needed is to install a very small pin in the bottom of the main cap. The early 289 Fords had such a pin, and your machinist should be familiar with them.
And yes, I agree with using a Buick rope seal. They will work in just about any engine that uses rope. You may have to remove the crank to install it though, as they are pretty thick. The proper installation technique includes using the side of a piece of pipe to tamp the seal down into the groove in both the block and the cap.
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David
newbie #4153
