The 340 auto cam was smaller (same as the 360-4 cam) The 273 manifolds were actually pretty good for the CID of that motor. even the cheesy Y design to the single exhaust was good engineering for that sound but they really cheaped out on the Y tube diameter, there is a major kink in most of them. if you could mandrel that Y fitting youd wake any 273 up. Its the same with the slant and its anemic 1 3/8 (almost) headpipe where it bends. Open it up to super six 2.25 and voila, instant gratification.
