Speedmaster Heads Heater Nipple
 

I'm installing a set of Speedmaster heads on my new build and was wondering what everyone is using for the heater nipple? The heads are threaded with what looks like 3/4" NPT, but I haven't found a direct fit part.

I'm thinking 3/4" NPT to smaller NPT reducer bushing and then just use an NPT to nipple, or AN, fitting...

Your thinking is correct. :)

This is what I used.

EDGE INDUSTRIAL 5/8" Hose ID to 3/4" Male NPT MNPT Straight Brass Fitting Fuel

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

I also installed a spacer i picked up from home depot to put inside the heater hose to block some of the flow like stock. I used a Hose clamp to keep it in place.

Hillman 1/4-in I.D. x 5/8-in O.D. x 3/8-in Long Natural Nylon Spacers

The Edge piece looks exactly what Edelbrock includes with their heads. Think it would be a good idea as Grandville said to reduce diameter to a 1/4" somewhere along the way as Pontiac did with their stock heater nipples. Reduced flow in and full flow out of the heater core should help reduce internal pressure spikes.