I think mariah has a 3rotor kit that used an HKS cast manifold with an extra runner welded on it... pretty embarassingly crude if you ask me.

 

Pic of mine purchased from Late Shift Engineering... after I spent around 8 hours to reweld all the joints and sand down the manifold flange as it was twisted from not being fixtured during the initial welding. The welds were absolutely the worst but the design is good. Some conselation...

built for a T-76 in a FC

 

That thing has to weigh 100 lbs!

 

Oh my twisted intestines!