These heads are on the big side for a 454 but it depends on the intake valve size,are they 2.25" or 2.30" intake valves. If they are 2.25" intakes valves you could make these heads work but it would be a higher rpm engine with a big cam and lots of compression. What size cam do you have? How much compression are you running? If they have a 2.30" intake valve then the valves would be shrouded in the cyl. You would have to bore and stroke this puppy out to at least a 496 with a big cam and lots of comp. and a 1050 carb. You should make 800hp then but it all depends on your budget and intention of this engine.