On points Victas you can get around the rev cut by hooking a car/motorcycle coil up to the points and running the coil off a battery. Thus building a total loss ignition system. From there they'l rev as high as the carby and porting allows. They've got a forged crank, beefy conrod and roller bearings for everything so provided you've got the carb, ignition system and porting to handle it, they are very happy to rev to the moon. The most I've heard is 16'000rpm out of an all out one built for a go kart in the 60s. 10'000+ is meant to be obtainable with basic porting and a carby upgrade.
They push more than 3HP standard. In some old advertising stuff I found a torque curve for the industrial version of the Victa 125. These use a decompression plate in the head (something like 5mm thick IIRC), a special throttle butterfly that only opens half way and a heavily baffled muffler. From the torque figures I calculated max power to be 2.8hp (IIRC, this was years ago) for that really restricted motor.
The stock intake is tiny and the carby is a bucket of poop. Fix these and you'l get good gains. Whilst the exhaust port at first appears humongous the actual port its self fairly small. You should expect to see gains from making it taller to increase the port timing. The factory "power plus" fullcrank Victas (used on the 24" & 26" mowers and some of the larger self propelled ones) had a squish band head and an intake with dual air filters. They also had a muffler with different internals. As you have probably noticed, Victas are the loudest engine on earth. Removing the muffler doesn't really do anything but make them sound like a machine gun, spit oil and flames everywhere and forcibly remove your eardrums via your nostils. Some people remove the decompression valve. There is no point in doing this unless you really feel like breaking your fingers. Even when the vacuum line isn't hooked up they work magically, though I have come across some that need the valve lapped.
Stock governed revs is 4000 on all 2 stroke Victas. Given their pneumatic governing system (be it vane or air pressure) it's probably more like 4000 +/- 1000. That's why they have the rev cut, if the governor got damaged/bypassed/unhooked ect they'd rev to infinity and launch the blades at your ankles.
In terms of torque, they have bucket loads of it as standard. It's what makes them such good lawn mower engines. On go karts we don't really care about having max torque 200 rpm above idle, hence why there is quite a bit of power potential. 2 strokes can have great torque, it just depends how they're set up.
Is yours a 125 or a 160? What Mk?
