I want to use Google in Opera in normal
http to speed up search; how can I disable Google SSL in opera?
What Opera version do you currently use?
If it's Opera 12, make sure you are not logged in to any Google account and type http://www.google.com directly. Just in case, clear cookies and caches before or use private browsing. Works for every Opera 12 install I encountered.
If it's Chromium based Opera 15, I'm afraid it has become harder to use HTTP because by design Chromium based browser abides the preloaded HSTS (HTTP Strict Transport Security) database. Google.com including most of its subdomains are included in that database. (see http://dev.chromium.org/sts)
Chromium actually has a way to bypass this via about://net-internals/#hsts, unfortunately this is either disabled or not available on Opera 15.