I know these are not going to help much in the HP department but this is what we have made to fit a 1990 Nissan GQ patrol. The stock exhaust manifolds dont fit because of the T700 adaptor plate on the rear of the engine.
Between the manifolds and the chassis rails is about 20mm
So here is the pics
Between the manifolds and the chassis rails is about 20mm
So here is the pics

