under just when you think you seen it all.working on a 55 272 and putting on the rear seal holder using the side rubber and nail i noticed how easy the sideseals went in their usually a pain to get down.the nail went in like nothing.i knew something was wrong.it would have leaked like a sieve.got another holder from a newer engine perfect.the 55 holder was to narrow.it still had its original rope and side seals.is this common with the early engines and i just never seen it before.