I like the idea of a real aircraft carb on the engine. These engines (12As) came here with 115 HP in the RX-2 and RX-3 in the early 70s. They had two stage 4 barrel carbs with tuned runners and pretty fair mixture control.

 

For emissions reasons the exhaust was abysmal and cost about 15 HP.. So the first Hop up trick was the exhaust headers. With no runner length you are killing off half of the power. The idea is OK. But I would add about 10" runners out to the box manifold. Put a trumpet bell shape on the runners at the junction with the manifold. I would also run the supply hose to the center of the manifold and add a bit of a horn shape. there as well. The engine breaths front back front back. The end runners can be angled in a bit and the manifold perhaps could be half the length you have it now. A thin stainless shield on the bottom to ward off the huge amount of heat from the headers. Plan for 200 PSI to account for the occasional back fire.

 

Lynn E. Hanover

 

 

 

 

Michael Silvius wrote:
> Any one see any obvious problems with such a set up?
>