engine life is truly determined by the end user more then any other factor... If used correctly a modified engine can last longer then the stock counterpart, however just the same the modified engine can be more susceptible to damage if its used incorrectly.... The modified engines make significantly more power then the stock counterparts, they can be tuned to a slightly richer mixture and still make exceptional power, as well they tend to run cooler then stock...and usually when driving them in races you do not need to push them as hard...... However because the modified engines are capable of revving much higher then stock they can be more prone to damage if a person tunes lean and bags the heck out of the engine.....with the extra RPM the engine needs to be properly lubricated, as the higher the RPM the more prone to damage they become from misuse ... I have had modified Picco's run for 12 gallons when properly cared for, and I have seen guys kill an engine in the first half gallon....but that can be said about stock engines just as much as it can modified, as truly it is the ends user who controls the engines lifespan more then any other factor...