603/Britannia Exhaust system

[PEU186F]

Yes indeed, the 410 has the same arrangement, with a view to blasting exhaust gas across channels in the inlet manifold in an attempt to achieve a faster warm up and hence less smog from cold. But I'd suggest your valve is a pretty rare survivor, mine had been removed before the car came back from California.

I was referring to a balancing pipe that ran between the two down pipes ahead of the silencers