I am going to be replacing the valve seals on my LG4 and I'm not sure which type they are.

Are they O-ring or Umbrella seals?

The heads are 416 casting.

Part numbers would be cool.

Thanks in advance.

 

o ring most likely, don't think gm ever used umbrella seal, there's a chance you may have postive type seal. if it were me i'd use o ring and postive seals both.

 

you have both seals all of the valves have the oring stem seals and the umbrellas are on the intake valves only why they did it this way I dont know I agree with ede i used both on mine cant hurt anything and they are cheap parts store should have them in stock