Thanks Trevor for your clear exhaust exposition. I have used twin injection s/s pipes into the s/s exhaust pipes on my refurbished CV WN4, but they are probably too close to the manifolds at the moment, so I will move them out further and lower, to inject just before a new s/s Y junction attaches to the rubber exhaust.
New keel bolts and jack u-pieces will be installed as soon as the snow clears. David Gray A49