I just put the heads on my 340 last night and may I say its going to be killer I've beefed up the heads, cam, and intake. Added a 670 avenger Holley carb and a 7 quart oil pan. The 340 was never offered in any package except premium. No 2bbl version and always a double roller timing chain with high flow heads. After 71 it did mild down some with cast crank and lower compression. But it still was better than what most had. Todays Hemis are what I would think of as an evolution of the 340. Dodge offers a small block 440 crate motor now and the hp is at 550. Now thats some serious pony power and with it installed you could just tell them its a 318