340ci vs 360ci engine
i was in the same boat as you about 3 months ago, asking 340 or 360. recently picked up a 76 cordoba 360. built correctly, some guys here have gotten roughly 20mpg, 350 hp, 400 tq with freeway gears. i cant personaly vouche on that but im planning on doing 280hp on my street 360 and expect 18-20mpg range so good luck!
link to the thread i got my info on 360s
http://www.forabodiesonly.com/mopar/showthread.php?t=89721