The same thing that happens with the defaults, except for that SHA1 is used for the multihashes instead of a stronger hash function.
What do you mean by "skewed"?
IPFS currently supports multihashes created using SHA1 just fine. Here's an example that works just fine for me using SHA1:
$ cat /dev/urandom | base64 | head -c 20 > temp
$ hash=$(ipfs add --hash SHA1 -q temp)
$ curl https://cloudflare-ipfs.com/ipfs/$hash