I am thinking of putting together my rotating assembly using light weight pistons, rods, crank, flywheel. I can understand all the benefits, but are there any tradeoffs with such a bottom end?
Paul

If you are talking about aluminum rods then I just started a thread on them about 2 weeks ago. From what everyone told me they are only good for 1 season (100 runs),if your car is street driven they will fail sooner.At around $500.00 a pop that is not a good deal to me.http://www.nastyz28.com/forum/showthread.php?t=73899

The only real tradeoff is the potential limitation for ultimate HP output (you wouldn't run lightweight pistons and rods on a blower engine making 1000 HP) and the lightening of your bank account. Weight removed from components such as cranks/rods/wrist pins reduces strength. (beyond a similar designed component with added material if that makes sense)