90 over 318 Head Gasket info needed !!

Just wondering how the webbing and main caps in those 318s stack up against 340 blocks, being that 340s have larger caps. I imagine that you can get some lightweight pistons and aftermarket rods that would come in at stock bobweight for the steel 318 crank to help keep the rotating mass down, but how well do those blocks live at 340 power levels? I am completely in love with this destroker 318, I imagine if the block could stand it that it could run insane rpm levels... Perfect for the class it is going to be running in!