I take it the rad is copper/brass. Brass tanks with copper gills in the core. When made new the pipes, drain plug, sensor bosses would have been soldered with high temperature solder. The tanks are then soldered onto the core with normal solder. Much better than the plastic tanks crimped onto the core.
I worked in a rad factory and we made rads for BL mainly but aftermarket ones for anything and everything. Triumph Acclaim was the first plastic tank version we did. Left there in 1984 and the factory is still going.
