Well, the old housing was well and truly warped beyond ever standing any chance of getting it to seal. I gave it 4 goes, used sealant, hand flatted it on a machined surface, checked it with engineering blue…I was ready to throw it in the bin. So I did. Luckily, I had another 90 degree housing off a later KP and, with a little modification and a new top hose, it fitted pretty well. I think it looks neater and it takes the load of the rocking engine better too. I don’t really care about that though…I’m just glad it holds coolant!