1970 dart for sale big block $8500 firm

He isn't much of a car builder if he can't tell you what the motor is by looking at it....assuming he has actually looked at it. But since you said "4 bolt heads" I looked at the pic again. There is no freeze plug in the end of the heads which would make them early closed chamber heads. They might even have the smaller 1.60 exhaust valves in them. Also, looking at the thermostat housing, that is an early style. So I'm thinking the whole thing might be early...like a 413. That, in my book, is way less desirable than it being a 440