CAUTION: HACK JOB...
Actually I came across this problem the other day..
The crown/race is bigger then the fork right?
I have a cheap raleigh vector frame I pulled apart (fork destroyed). It has 1 inch threaded head and got a free fork for it. C/O a friend. The fork is nice with columbus drop outs.
I was so excited to put it together.
When I got home i put the 1inch crown on the fork.
It the crown was maybe 1mm (1/32") too big. Sad...
This is because some older forks had a different standard.
My remedy was to use a piece of thin cardboard as a shim.
Call me a hack or what not but it worked!
You could use something metal but whatever. paper compresses nicely.
I simply wrapped a small piece of cardboard around the steer tube then slid the 1inch crown around it.
Then I pressed the crown all the way down. If you have a crown setter, all the better.
After that I just peeled the excess cardboard away. It fits really really snug.
You'll know what to do after that.
I'm going to warn you that this is sort of frowned upon by prestige mechanics.
but its REALLY an inexpensive way to get your bike up and running.
I'd suggest using this method if only if you're in a bind.
IE, can't find the correct headset.
I'd probably use metal or some sort of plastic instead of cardboard next time.
So far this works fine. The fork is solid with no stuttering.
Hope this helps