there is things about the head i do not like .port size will not match any thing out of the box . head chamber will only seal with a 4.625 fire ring head gasket not to big of a deal were your useing a 4.600 bore bbc but i would never use them heads on any thing that big of bore the 396-496 so with a 4.125to 4.310 .that chamber is to far off . them two things stop me . there are many heads i can get and for the price i can get them for i have a very hard time wanting to spend added time on a sub quality part making it work when there is stuff out of the box that fits better