Water pump housing nipple size

[CudaS0383]

My '70 383 cuda came to me without the heater hoses hooked up so trying to get it back to factory condition.  The car also came with factory A/C.  Currently there are plugs in the water pump housing and I bought factory correct hoses which are 1/2" and 5/8".  Does anyone know the correct size and location for the 2 nipples that go in the housing?  It looks like my housing has a 1/2" hole and a 3/8" hole but that doesn't seem to jive with the hose sizes.  Any insight would be appreciated.  Also, where can I buy the correct nipples.  Thanks much!

[Cuda Cody]

1970 is a 1 year only water pump housing in terms of the hole sizes.  Post a photo of what one you have.

[CudaS0383]

My car is at the shop getting A/C put back in her so don't have a photo that I can post right now of what is in there.  Here is a housing that I got from the previous owner with a p/n of 2780987-12.  You can see a 3/8" hole and a 1/2" one.  I think I will go there tomorrow to get a picture of what is in there.  Thanks for your help.

[JonH]

Just did this. Look right below the 1/2" plug and you will see another 3/8" npt outlet. Those are the ones you are looking for. The 1/2" plug was likely for a temp sender. Can get the nipples from multiple places. Start at Roseville (a site sponsor) or Mancini.

[CudaS0383]

OK got pics today of what is in the car and measured the nipple holes.  Both are 1/2".  I think the one closest to the alternator (on the left from top view) is the output of the pump.  Also you can see the p/n of the housing that is in there.  So these hole sizes differ from the previous picture so not sure which one is correct.

[anlauto]

You'll need this to bring it down to a 1/2" hose

[CudaS0383]

OK thanks for all the help. 

From what I have read on line, the hose from the pump housing to the heater core is 1/2" and the return hose is 5/8".  This was done to cut down on noise.  Does this jive with what you know?

This is what I got.
https://www.yearone.com/Product/Challenger-Cuda/PK68

[Chryco Psycho]

This should be what you need , you do need the longer nipple behind the alt mount bracket
https://www.rosevillemoparts.com/product/heater-hose-nipples-70-78-big-block-and-hemi/

[anlauto]

Pretty certain this is how they go...

[anlauto]

This should be what you need , you do need the longer nipple behind the alt mount bracket
https://www.rosevillemoparts.com/product/heater-hose-nipples-70-78-big-block-and-hemi/

The 1/2" hose one in this kit will NOT fit his water pump housing, he'll need the fitting I pictured above.

[CudaS0383]

Yes agree with Chryco but they don't specify what size the NPT end is so I called them.  They didn't know and didn't have any in stock to measure so I found some on Summit and ordered them.

Also, agree with anlauto regarding which size hose goes where.  I learned some info that I didn't know regarding NPT pipe sizes.  Even though the hole measures about 1/2" it is technically a 3/8" NPT fitting.  Luckily I found this out before ordering my parts.  So much for being straight forward!

[Chryco Psycho]

Pipe is measured differently , it is always ID not OD so measuring the hole in not accurate pipe size , Dorman carries a lot of universal nipples even in the longer lenghts

[Brads70]

Another way to figure out what the size is , google tap drill sizes NPT . This gives you the tap drill size which should be pretty close to the size of the hole.

[CudaS0383]

OK all set.  Got my parts from Summit yesterday and can now finish the project.  Thanks everyone for your help.

[anlauto]

Awesome