Wow that's interesting, I wonder just how he custom built manifolds to fit?
https://www.marineengine.com/parts/barr ... direct.htmnow I'm not sure if there is some added complexity if the engine has EFI vs a carb due to bracketry, but I bought Barr Marine manifolds and elbows for my old OMC 5 years ago and they fit and worked fine.
https://www.volvopentastore.com/Exhaust ... _id.777152keep in mind that if you have an OMC Cobra from 1994-1998, it is the SAME, as a Volvo Penta SX Cobra from the same years. And it looks like they are still available from Volvo.
I got some exhaust parts to do my conversion (I converted from the old one piece V6 manifolds to the newer 2 piece set up where the manifolds & elbows are available in the aftermarket) from VP because the OMC versions were un-available, but no problem getting the same exact parts from Volvo.