'64 Grand Prix Tri-Power Waterneck
 

I have a few odd watenecks that I believe are for '64 Big Pontiacs. The casting number is 9776545.

The shape is nearly identical to the '66 GTO and big Pontiac waternecks, but with a different casting number.

Can someone confirm?

Here is what it looks like.

Dick,
1966 parts book confirms that part # is a 1964 full size tri-power water neck.

Here’s progress on the Tri-Power.

It’s going to go on a ‘64 Grand Prix. The block is a ‘64 421code 45B, which is the 421 HO, factory rated at 370 Hp. Heads are ‘64 421 HO/‘64 GTO casting #9770716.

The short block is a Dan Whitmore build.