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5/16" or 8mm X .500"-.535" Viton Valve Seals, Flex Body Type, 4 Cyl Set, VSS-403, Set of 8

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Calculated at checkout

Product Description

Positive Valve Seals, Blue Viton

Valve Seals, Flex Body, Universal Fit

Size- 5/16" or 8mm

Guide Diameter Range- .500"-.535"

Set of Eight seals


If you’re looking for quality valve seals, you’ve come to the right place!

We continue to build our valve seal line and now have one of the largest selections of valve seals available online.

These are from our FLEX BODY SEAL family


     Specification Data:

  • Size: 5/16” X .500"-.535"
  • Fits: 5/16” Valve Stems.
  • Fits: .500"-.535” Guide Boss Diameter.
  • Wall Thickness per side: .072" 
  • Total Wall Thickness: .144"
  • O.D. See Note below*
  • Seal Material: Viton
  • Material Temp Rating: 450F
  • Seal Type: Flex Body
  • Number of seals included in purchase: Eight
  • Valve seal protector sleeve included? YES- One 5/16" sleeve is included with the first set of eight. When buying multiple sets, one additional sleeve will be included with every additional 2 sets ordered. (16 seals)


* Based on the fact that flex seals fit a range of different guide diameters, the actual seal O.D. cannot be predetermined without knowing the existing guide diameter for the specific application first but once known, it can be easily determined using simple math.

To figure the seals outside diameter after installation, use the total wall thickness specification from the chart above and add it to your applications guide diameter.

Let’s say your applications guide diameter is .502” and the total wall thickness is .144”

Guide diameter + total wall thickness = estimated seal outside diameter.

Example- .502” + .144” = .646” estimated outside diameter.

The formula won't be 100% accurate but will be close enough to make an educated selection.


     Applications for this seal size:

  • Universal fit, flex over a range of size
  • Any 5/16" or 8mm valve application w/ a guide diameter between- .500"-.535"


Need a different seal? Check our other categories and if you can’t find what you’re looking for, send us a message.


Alex’s Parts, the smart choice in valve train products~

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