3877660 Water Neck ?

[1972convss454]

I have a question about the aluminum GM water neck part number 3877660.
I've seen two versions. One has a tab with a hole and the other version does not have the tab.
What is correct for a 1970 Chevelle L78 or LS6?

[SS427]

What you show in the photo is correct for a 70 big block.

[67 Nova Boy]

More then likely the tab broke off of the other one for a throttle return spring or some thing like that.

Dave
67 Nova boy

[Pacecarjeff]

2 versions of the 660 housing. One has numbers on the neck as shown, other is on the base. Both have the tab. If no tab, then it is a 128 housing.

[1972convss454]

Thanks Guys!