light weight big block

I'm building a standard 451 which basically is a 440 crank & rods stuffed into a 400 block. Takes very minor machine work. Reason I mention this is you may already have these parts & the pistons are very light, about 750 grams compared to the 440 six pistons which are in the 1000-1100 gram range. My old 440 TRW pistons on the shelf are a whopping 1125 grams. Dropping all the internal weight will make it rev like a small block.