243's
 

How do I know if my valves are sodium filled or not?:eek2:

try the internal engine section.

only the Z06 243 heads came with the Sodium filled valves,,which would have also came with the yellow beehive springs.
If your 243 heads have just regular factory beehive springs that aren't yellow then no they are not sodium filled.

Unless someone has changed the springs???

Also I have noticed that sodium filled valves will have a light greyish almost white apperance to them after being used.

hope this helps

weigh them.

there are other 243 heads with the yellow springs that did not have the sodium valve springs.. gto's did

^exactly which is why you have to weigh them.

bingo

Mine came with Yellow Beehives and they are 4-15/16 in length.