Of course there are. Remember though, Viton seals aren't necessarily positively on the guides. Viton is a brand name for the type of rubber used on the seals. You can get umbrella seals made of Viton. Here's what I used on my slant 6 head.Keep in mind though, that .625 is the inside diameter. You need to be sure the ID if your inner sprAng is big enough for the OD of the seal. I feel sure it will be.
SEALS