Why did Buick put a sight tube on my timing indicator gauge?

I'm not sure what this sight tube function is. My tdc #1 aligns with it so I think my balancer may have slipped. I always thought tdc was supposed to be at 0* mark. 72 350.

 

I've never seen that. Is it a CA. State emissions car by chance?

 

No. Indiana

 

No smog pump but one triangular hood seal.

 

Its what is used when the car is hooked up to a Sun machine or engine analyzer . Its for a magnetic timing pickup . It didn't come from the factory like that . Would have been on later year engines like in the late 70's or 80's

 

Came off a v6

 

So it is not correct for my year but timing marks should be identical?

 

And 72 service manual shows this one.

 

I would like a correct year and patina timing indicator. I will post it the wanted section. Thanks everyone!!

 

I thought my timing cover was original but my memory isn't what it used to be.

 

I am Jason . But you youngsters should know with AGE comes EXPERIENCE !

 

They would only be correct if the dampner was the same diameters

 

I worked for a shop that had the first Sun Interrogator in PA NJ and Delaware . Remember that one ???

 

Hugger is correct, the original timing tab is cast in the cover, late replacement and aftermarket covers use the bolt on plastic timing tab from the V6