289 valve stem seals

[1967 eight barrel]

The entire automotive industry has migrated to valve stem seals that press onto the valve guide in some fashion. While rubber umbrella seals "were" the norm , time marches on.

What you did fail to take into account is that you can't run performance springs without changing to positive seals. If you have a trailer queen that is being left completely stock, by all means use the umbrella seals. FEs tend to wind up with a puddle of oil up top if you don't restrict the oil to the rockers. If you have the heads off, install positive seals. Few reassemble heads with 50+ year old valve springs.