I swapped out my rear main seal on my 66 289 Coupe because it had a slow leak. I replaced the original rope seal with a rubber seal from FELPRO and it still leaked. Everybody said that you HAVE to use a rope seal, so for a 3rd time I replaced the seal and put in a Rope Seal. Guess What, it still leaks!!!! Does the crank wear after awhile, I looked at it but it didn't look bad, is there a oversize seal to put in or do I have to grin and bear the leak until I can replace the crank?