Trick Flow advertises them to fit the 383, 400, and 440 so I believe they do when i first looked at getting aluminum heads I didn't know that they can't just be slapped right on wish they could I also do not know how much it would cost to have them checked i don't need to have them ported do I? another reason I want aluminum heads is because TTI's full length 3 inch headers say they fit all the aluminum heads we've mentioned and 906 452 915 but did not mention 516 heads