Nope - havent changed tyres size!
I know on a newer late model car when a 100 amp alternator is working and giving all its got it takes away 2 hp. On an older 100 amp alternator i would on suspect 4 hp. Instead of wiring up a bunch of crap why not turn up fuel and boost a little bit?
My point with the cooling fan is that there is not any reason to cut power to it. It is sensor controlled and so only ever comes on if you actually need it to. Disabling it at that time would be very unwise. Likely a WOT (hey, where's the throttle?) would never see the cooling fan come on, but then again if it should, not letting it would not be worth the brief hp improvement...
Andrew
If the alternator is killed at WOT the cooling fan will run off the battery so it won't rub power from the engine anyway.