I just slide a correct ID/OD house in/on each. Ie:
I cut a hose that fits the rad bout 4 inches long (or whatever), stuff it inside the other,
slide the bigger ID one over it - (& both) up to metal rad's flange'n tighten a clamp over.
The inside one (carpenter language) pads out
the other. Might need grease between the 2 hoses? I usually dont. Esp when usin a shorter
internal hose (just the length of the rad's flange (almost like a 'bushing')...?
This way I can use 'properly' "molded" hoses even if wrong IDs for radiator. Obviously U cant
make a 3 inch hose fit a 1.25 flange (well, I guess U could if doing this 2, 3 times over. Might
catch the observer's eye at that point tho).
I service alota "poor" exhaust customers, ina rush, commercials that want just back to wrk (esp farmers around here this timea yr) and do
same w/metal (sleeve scrap from the pile, pipe inside pipe) rather than wait for pipe delivery or pay for store bought when there's plenty lyin round.
8^ )