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Positive Valve Seals, Poly Acrylic, Early Gen 1 SB Chevy, 11/32" X .570"-.590" Guide Diameter, VSS-412P, set of sixteen

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Product Description

Flex Body, Poly Acrylic Positive Valve Seals

Valve Seals, Poly Acrylic, Early Gen 1 SB Chevy, set of sixteen

 11/32" X .570"-.590"


This seal was designed many years ago for use on Gen 1 SBC heads starting in the early 60's to around 1980. They were intended for use with heads which came only with O-rings seals. (no other seals, just the o-ring)

Most of these early heads have guides in the .570"-.590" range.

Folks with old Gen 1 SB Chevy's engines that burn oil and/or smoke are always after an easy fix to reduce oil consumption through the guides, these are the only seals we have found to fit 11/32" guides in the .570"-.590" diameter range.

Gen 1 SBC includes: 283, 327 and early 350 engines.

Please be aware, adding positive seals to early castings will reduce retainer to seal clearance. Since the factory guide sits up taller than later heads which came w/ positive seals, adding them to early heads will reduce the distance between the retainer and seal at full lift.

The best way to retrofit early heads is to have the guides machined and lowered at your local machine shop. They can machine the guides outside diameter and height in one set up, then fit the guides w/ premium viton fixed body seals.

Unfortunately, many folks are looking for a way to add positive seals without taking the heads off the vehicle, they just want to try to reduce oil burning and smoking in the easiest way possible. If this is what you working towards, these are the only seals we know of that can be fitted to the stock guides without machining.

Just be aware these are intended for stock cam lifts so engines with lifts over .400" lift may experience issues related to the retainer contacting the seal at full lift. If this happens, the seal will get beat up and damaged from the retainer smashing into it.


When installing positive seals on a used Gen 1 engine, it is suggested to replace the o-ring seals with premium viton o-rings. Unlike early Nitrile rubber o-rings which become hard over time, modern viton o-rings have a much higher temperature threshold which makes them resistant to hardening so it makes sense to replace them at the same time.

Check our other listings for viton o-ring seals.


     Specification Data:

  • Stem Size: 11/32”
  • Guide Diameter Range: Between .570" to .590"
  • Seal Material: Poly Acrylic
  • Material Temp Rating: 350F
  • Seal Type: Flex Body
  • Number of seals included in purchase: Sixteen


Order quantity 1, get a set of sixteen seals.


Thanks for looking.


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