[kitcarbp]

Here are the three OEM "style" cast iron water necks I know of to fit the 429/460. These are aftermarket examples from "4 seasons". Made in China.

The (# 84859) with the single threaded port in the top is for 1969-1977 carb, car and truck applications. The chrome ones (that all warp) in the aftermarket are designed with this same single port.

The one without the threaded port (# 85185) (pictured here) is for the fuel injected 95-97 truck 460's.

There is another one used (pictured here) on the 78-94 that is a bit longer and has 2 threaded ports. This is 4-season part number 84860.

I also attached the pic of my OEM (GM... ooh bad word) air bleed valve I use on the top of the therm housing to bleed air out of system when filling. Makes my life a ton easier.

There are a few more that were used in production I think but these are the popular ones. The 351C therm outlets have same flange and bolt pattern but are straight up.