904: should I switch to 727?

There is a "torque limiter" which protects the transmission, which is when the rear tires slip. I would expect that if using typical street tires, with no downforce like from a trailer tongue load, the tires would always slip before transmission parts break, even in 3rd gear at low speed. People who break transmissions and differentials, plus twist driveshafts are usually drag racers using wide sticky tires.