I'm not exactly sure what you mean by gaps. If you mean an area like a hellivator or a subway you've created that's supposed to create a large amount of space between blocks, anything within the "V" that is corruptible will be corrupted. After the V is created, you can use structures such as Hellivators and Subways to quarantine off areas from getting infected, or make them and then purify an area you don't want infected, but they won't be able to stop the initial "V" that's created after the WoF is killed.
So if you were you surround the corruption pre-hardmode in a non-corruptible block then enter hardmode, would the initial “v” pass through said blocks?
In short: Yes. You can't make areas safe until after the big 'V' happened. When the ancients are unleashed, the V will travel across the screen, jumping all the gaps and barriers that you might have made.So if you were you surround the corruption pre-hardmode in a non-corruptible block then enter hardmode, would the initial “v” pass through said blocks?