I've researched this idea for a long time. The GMC rod swap is the only economical choice for the Chevy engines. You can offset the total rod and piston weight some by going with a custom piston, but thats about the only choices out there. Custom billet steel rods aren't going to be much lighter either than the stock 261 or GMC rods. So the lighter custom piston is about the best way to reduce the overall weight significantly.
