Jon’s post above is 100% right, then again its 100% wrong, mostly because your comparing many different types of Animals.
We have raced animals since day 1, actually several years before it had the Animal name, we started with Intec’s.
Most people recognize the LO 206, WF, and Animal names, there’s actually several variations and more versions of these.
Heres a rough set of HP numbers
LO 206 8.8
WKA/IKF Animal 10.5-11
WKA Limited 14-15
Opens 24 is easy, 30 is possible
That leaves WF which is kind of a odd duck. World Formula came about overseas as the name of a complete class. This was at a time when CIK though once again the end of 2 strokes was around the corner. The concept was for multiple engine brands and there was a set of guidelines the proposed engines would need to meet. Notable here is all engines were to make 15 hp
Does a Briggs WF make 15 hp? Out of the box, not on our dyno, but more important , CAN IT? Absolutly.
The WF uses a bigger cam, bigger carb and more compression then the Animal. Those things allow it to make more power then an Animal, HOWEVER, if you understand engines and making power, those things produce that extra power at a higher RPM. The Briggs WF has a Rev limiter to increase life and keep things under control. Take it from 7 grand to 8 grand or more and there plenty more HP there.
One other thing that should be touched on here as long as your comparing speeds. My kids have done Road Racing since they were 12, Theres a great deal of differance in chassis in this. For Animals we have classes that use chassis right off the sprint track, we also have Road Race class that use Sit up sprint body work. Not a lay down chassis, but far faster then a sprint track body work kart with a full 38 in nose. CIK body work is about useless for Areo ( yes we’ve run classes with it)
At Blackhawk Farms, a 2 mile track in the midwest, using exactly the same engine rules (WKA BP), sit up sprint karts will lap the sprint karts in a 15 min race.
The second race at Blackhawk as far as I know was the first time a Stock BP Animal broke 100 MPH. We have been in the 95-98 range for years. Limited Mod Animals are usually in the 110 mph range. Remember these speeds are with extremely good Road Race specific chassis, not CIK. To understand that compare CIK, 125 shifter times, to the road race 125 shifters. Areo is everything