I went ahead and picked up the grubby Viscount Aerospace Pro I looked at last week. Of course, the DEATH FORK needs to be replaced. I am thinking of trying to find a good used chromoly fork with a chrome finish so I can preserve the original look.

Is a 1" diameter the correct size?

The bike is currently equipped with 700c tubular rims. What are the changes I would need to do if I find a 27" fork?

1" should be correct.

make sure you have enough steerer tube - measure from the crown of your current fork to the top of the headset (better yet, just take the fork out and measure the steerer length).

If you find a good deal on a fork with a steerer that is too long your LBS can cut and re-thread down to the proper dimension. Obviously nothing can be done if the steerer is to short.

You may also have to replace your stem, as there is some variation in the inner diameter of steerer tubes.

I would not bother with a 27" fork.

You don't want to have to find 27" rims for this.

good luck

I'm no Viscount expert, but are you sure it's 700C originally? The Viscount center-pull brakes should probably work with either and I thought they had 27s from the factory. I could be wrong. I'd find that out before you go looking at forks. In any case a 27" fork is not going ot be that much different. If you have 4mm more vertical travel in your front brake pad adjustment then a 27 fork will work fine.

Cheers,
Kar

Mine was definitley 27"
Even if they are 700c, the 27" fork length shouldnt be an issue.
Is only about 1/8" difference.

There isn't much out the web about these bikes but it appears that the Aerospace Pro came with both 700c tubulars or27" clinchers. The Aerospace GP came with 27" clinchers.

https://moonmoth.net/Bicycle/viscount...Brouchure8.jpg

Thanks for confirming that it is 1" diameter.

Another question. I'd like to know the year of this bike. Does anyone here know how to decipher the serial number? 009639 KB