First of all a set of adaptor stubs were turned down from some aluminium tube. These are machined at one end to lock into the standard Honda rubber couplings at one end, then crushed and welded to at the other to the stock B series inlet flange. These stubs were also bored out internally to match the bore of the throttle bodies.

 

The stubs were then gently crushed in a hydraulic press to match the contour of the inlet flange as best as possible. Great care was required to crush the tube in the right area - it was also surprisingly springy and required a fair amount of force to retain it's shape. A rubber former was turned to the ID of the stub and inserted in the non-crushed end to help it retain its shape.

 

Continual checking of each of the stubs during crushing was very important to get each stub matched as best as possible to the flange, and to save time on welding and machining.

 

Once things were looking good, it was time to have the stubs welded on. Thankfully the throttle bodies are a great jig to hold everything in alignment - the stubs were tacked on and then the bodies and rubbers carefully removed as they would be damaged by the heat of running the complete beads.

 

 

The completed manifold mounted on a spare B series engine to get an idea on how it would all work out. All that's left to do is some filling and porting of the walls, to smooth out the transition between the stub and flange.

 

Test fitting the manifold on the car, with and without the bodies.