8500 is what the last RPM headed 6bbl 505 cost...minus the carbs, but including the 6pac intake. That's a 600hp, solid flat tappet, roller rockers, good parts, good machining, etc. This guy is selling factory parts at that?? Year One is closer with the 4500 deal, but I shudder to think who is doing the work for them, because they typically double the cost to arrive at a selling price. Also, and F code is a '70 440. Not a Magnum 440. Not that it's any different in parts or wuality, but it would carry the HP stamp on that pad. This one doesnt. A similar build using good parts and great maching should cost in the $3800 range starting with your core. With core charges in the $400 and up range, $8500 is nuts. And, technically, he cant ship it ready to run and pre-oiled. The oil drains out of the system while it's in route, and the pan needs to be empty of excess oil. Run away from that.
