Replacement vacuum hose source?

I'm in the process of replacing all the vacuum lines under the dash on my 1983 280 ZXT, and I can't find vacuum hose with an exterior dimension matching the original. You wouldn't think this would matter, but some of the vacuum fittings are recessed and have a "ring" around them into which the hose must fit. The oversize OD hose doesn't go - I've had to cut off sections of the old hose and use a fitting to attach them to the new hose for the last couple of inches.

On the engine side, I still have original clamp fittings which won't go over the slightly larger OD hose, either.

If you have replaced the hoses under the dash - what did you do? Did you just force the replacement hose on (a spray of silicone does help)? Or did you find matching vacuum hose somewhere, like a Nissan or other Japanese car dealer?

PM messages would be appreciated in addition to responses in the forum.