Increasing fork height on a CX bike

[lune ranger]

I’ve just built up a second hand Transition Rapture CX bike. It’s being commissioned as a faster, leaner replacement for the Fargo I’ve been using as an all rounder.
It’s certainly riding faster than the Fargo and is also a good 2kg lighter even though it is similarly an all steel bike. A few equipment swaps could see it drop up to another kilo - maybe.
In order to achieve this an obvious switch would be changing to a carbon fork. The problem is that the Rapture fork is 395mm a-c
I’m having difficulty finding a reasonably priced carbon fork that height. There are plenty of options at 425mm.
Is adding 30mm to the a-c dimension going to screw the handling? My mental image sees that the front end would obviously be higher, this is not a real problem as there is maybe a 40-50mm step down from saddle to top of bars at present. I’m also envisaging that the head and seat tube angles will slacken. My guess is not by much though maybe a degree or so. Am I right?
What do those that know about this sort of thing think?

[Gari]

If it’s a tapered headset there’s this.
https://www.finnacycles.com/en/forks/13 ... -fork.html
409 a-c so not massively different.

[lune ranger]

If it’s a tapered headset there’s this.
https://www.finnacycles.com/en/forks/13 ... -fork.html
409 a-c so not massively different.

Nice.
Should have maybe said they need to be 100x9 QR and that ‘reasonable price’ means <£100

[jameso]

Is adding 30mm to the a-c dimension going to screw the handling?

IME/IMO yes, but that depends on how well it handled to begin with. It'll take a degree and a half off the angles and raise the BB almost half an inch. It's rare that those changes would be a good thing for a CX/gravel bike that handles well as it is.

My take would be to stick with the steel fork. It'll be 500g heavier but I don't own a bike where 500g saving on a fork is that important it offsets how wary I am of carbon forks (not entirely rational, but not totally irrational either). And I swapped a carbon fork out on one of my bikes and found the steel alternative rode smoother.

If you could find an Arkose fork that would be a swap-in, they're 395 or 400mm A-C dep on year, 50mm offset.

[lune ranger]

Thanks James. Was hoping you would speak up.
I’ll just wait for a better matching fork. I like a bit of eBay detective work anyway.
As it happens the bike handles very well indeed and is asking to go faster than the Fargo ever did so I dot want to spoil that