Running at 190F is more likely going to damage your engine as the liner is not getting to a high enough temp to expand, your piston will be slamming into the liner which will be very tight, casuing stress to the rod etc

If you have healthy smoke and the car sounds good you cant go wrong. If it sounds good its running good, if its smoking it means the engine is getting lubrication. Up the track, some cars are running 230f screamign there balls off and the likes of the Go engines are running 260~270f screaming there balls off. Both puffing out blue smoke.

So it also depends on the engines too, try running a go engine at 230f it wont even be able to turn the wheels. I tried it, and the poor thing couldnt move! go it back up to 250 and it was running but groggy. litlle leaner (run at 265~270) and it was screaming with healthy smoke!