Where can i find an exhuast manifold that i can mount an external waste-gate on ?

 

Other than ordering up a custom fabricated manifold the only option is the "R" exhaust manufold part number 30637921.

What is it you are asking about when you say external wastegate ?? The wastegate is built into the turbo not the manifold.

Are you thinking of blow off valve ??

Why try for 500 CHP on a Volvo when that degree of performance would be so much cheaper and easier on almost any other engine

 

An external wastegate it mounted on the exhuast manifold, and controls boost by dumping "Waste" gasses from the exhuast manifold, rather than the turbine housing. They are more efficient, and respond faster than Internal wastegates. See here:

Also, i found one of these bad boys right here:

TIG-ART Volvo SuperPro Turbo Manifold | Turbo Manifolds | TIG ART

And as for a 500+ HP volvo 850 ? Why not have something that nobody else around you has ?

 

Sorry, thought you were confused about the wastegate being part of the exhaust manifold when you were talking about this instead: