ok...now i'm being technically curious....at what point does one engine is considered as a race engine?...when it no longer uses OEM internals?...when it's HP goes beyond certain limit?....
Nolah for hp limit.. even street cars can make quite nice hps.
I think for stroked and bored versions, they still are quite drivable and street legal.
A (true) race engine is classified so because it's design and tune requires special race regulated fuels, which is not the same stuff that comes out of our petrol stations.
One thing is maybe limit the fuel and use of octane adders, but I realize it's difficult to regulate and difficult to prove during a protest or dispute...
But No matter how crazy race mods done to the engine, the fuel and use of octane adders will limit the power output, so if it's applicable, state the rules. Maybe you won't find out today that the person is using race fuels, but for sure that person cannot hide forever the fact he is using race fuels.
So we'll be sure will never see a real 1.6L with 200hp one...or at least one that doesn't blow after a few runs. :P
I think J's idea of a time bracket is better. People will learn more about getting the engine to run faster with stock setup, and as more people turn pro and hit higher times, then increase the bracket, or have multiple time brackets. Close fight much more fun to watch than big difference drag race. Same for the competitors, can start with suspension tweaks, minor fuelling tweaks just to beat that guy that overtook you by 0.5secs. :P