346236 BBC Pass Oval Port 402 454 Cylinder Heads. Cast dates J 21 74, J 31 74, 1975 passenger car applications. Heads have been disassembled, cleaned, magnafluxed and check out OK. No cracks or stripped threads present. These are passenger car, high velocity "peanut" port cylinder heads that are known for producing exceptional amounts of low end torque and the highest highway fuel efficiency possible on big block engines. These heads are compatible with OEM 384740 Rochester Q-Jet intake manifolds. Head J 31 74 has a lengthwise scratch on the combustion chamber side which should not be a problem if you are using composite head gaskets, see picture detail. We…