yep, 440 pistons in a 400. done it. the late 70s replacement piston. i think the pn for trw forged was 2388. i just used a cast piston, badger i think.no mods. was down in hole about .010. i think someone here used a 2266 but had to modify it to clear the head as it was positive deck. was once probably the cheapest way to get compression in a 400. there are probably better options now.