Nipple Size?

[Stu Twin]

But seriously...
We need to get some fittings to attach the heater hoses to our new water pump on the 69 Sport Satellite.
As the car's a 69, the 2 bulkhead hose outlets are both the same size (5/8" ID?)..
As far as i can tell, from 70 onwards, they fitted different size heater hoses.
And the tapped holes in the new (aftermarket?) water pump, are 2 different sizes.
What i'm not sure is, can you get the screw in heater nipples for the w/pump with 2 different thread sizes but the same hose dia?
I can't quite tell from the Year One etc descriptions.

anyone come across this?

[RobTwin]

To illustrate the question...
First pic is our original engine with heater hose nipples visible, both the same size. I think this was an ally aftermarket housing.
Second pic is the new one but to me it looks like a cast iron housing and has a casting number visible. The plugs fitted in the heater hose positions appear to be different sizes...

[Birdman]

Hi Rob/Stu, I bought some off ebay.com and from memory they are the same thread size. Here's a link to Mancini Racing
http://www.manciniracing.com/hehonib.html
Satellite is away in storage so can't go and check just yet. Chris

[RobTwin]

Thanks Chris. Yes, I found those Mancini parts last nite too. I was going to post but had tinternet probs thanks to Virgin
It's since been suggested by Koffel to use the larger (spare?) hole in which they have fitted a 1/2 NPT plug, and replace that with a 1/2 to 3/8 reducer and 3/8 nipple and connect the hose that would normally go to the position that is currently occupied by a 1/4 NPT plug.

So... does anyone know where to get a 1/2 to 3/8 NPT brass reducing bush?