I am looking for a set of 27 inch wheels with a modern cassette hub for 8 speed. Who has them that are not custom?
Preferrably 3 cross 36 holes alloy rims.

You might post as a WTB because that is a pretty rare request, unless someone has built a set for a canti equipped touring bike like a Mid 1980's Trek.

Your best option is probably to find a pair of wheels with a freewheel hub, which should be reasonably cheap since 27" wheels are obsolete, and find an 8 speed hub that matches close enough that you can just switch the hubs using the same spokes.

But one has to ask: why? Is there some reason to prefer 27" wheels where you live? Around here, there is not.

Are you trying to modernize a bike with the older 27" wheels?

If looking for new wheels, why would you prefer 27 inch over 700c? Almost all bikes can be readily modified to take 700c wheels. Plus bikes old enough to take 27 inch wheels are generally set up as 126 mm in the rear.

I will take it one step further back. I associate 27" wheels with 5 speed freewheels and 120 spacing.

Exactly. Keep it traditional. But then, it isnt my bike and tinkering is what we all like to do.

With my statement, I am not suggesting that you must configure your wheels that way. In fact, HF Record hubs are linked, in my mind, to DB spokes and sew up rims. Nothing classier for late 60's and early 70's bikes at the upper end.

I want to take the wheels from this, they are steel rimmed, the rear is dinged and the front is untrue, and upgrade it to 105 8 speed to set up a 1/2 step gearing(as in the chart below). You can see that the front brake is bottomed out already so staying with 27" wheels would be easy and keep some of the vintage look. I have 105 RD, FD, crankarm and 39t/42t chainrings, just need 8 speed indexed DT shifters and clamp. I have some SR randoneer bars and Dia-comp aero brake levers that I want to put on along with the setup mentioned. Oh yeah, I need to replace the crappy seat and post.
and I want this setup

And BTW, 27 inch wheels are not obsolete, they have class and and also over here you can find anything from 24 1 3/8 to 28 1 3/4(25X635)

Just to clarify, here in the C&V everything is obsolete when looking from a crabon-fiber, electronic shifting roadies world.

I do have some 700c rims and could use them but they don't have the class that 27" wheels have, and I have a long reach front brake that will fit right on.

Also my other bike that I want to build up is another Raleigh Grand Prix (76) that came to me as a frame and fork that I am going to build up as a SS with 27" wheels that I built up using some new Araya rims and a set of Shimano hubs that I laced up myself, centering a 6 speed hub as a single speed. This will keep my 2 bikes I keep in the States similar and easy to work on.
This is my stable of 700c bikes here in Cambodia

I had that bike-- always thought having the rear stays wrapped around the seat tube was interesting. High flange hubs. Heavy bike -- did my first >100 miler day on that one. Pretty ugly green. Mine was a triple.

This sounds like the perfect time to learn how to build wheels if you want something that particular.

I'm not sure I agree about the "class" associated with a 27 inch rim, how much class can you fit in those extra couple mm. Find a nice set of 700c rims and peel off the stickers or a polished classic styled modern rim. Get some long reach center pull brakes, who would really notice the difference.

Make sure the seat- and chain-stays don't interfere with the cassette and chain with an 8 speed cassette. I have a Raleigh Grand Prix from a few years after that one and my modern cassette hub didn't work. I am going to use the stock Normandy hubs laced to 700C wheels when/if I get around to building it.

Edit: Sun CR18 is made in 27" size, but I doubt you will find it pre built with a cassette hub.

I get it.

I took a bike that was at 700c and changed it to 27" just so I could use a particular set of brakes that wouldn't reach 700c.

I don't look at it as bad, as most of my bikes are 80s tourers that work best with 27" wheels.