I assume you're talking about the old TRW/Speed Pro pistons?
True, they are heavy. However, they were once all there was. People used them in droves. What you didn't see in droves were engine failures due to heavy pistons.
I am sure there were some, but nowhere near as many as pistons used. Bottom line is they WORKED and STILL work. Is lighter better? Yeah but it;s probably splittin hairs on all but the hottest of race engines.
