Fair price for 340?

You may find putting a 360 in may be cheeper. A complete 340 can range from about $800 needing a complete rebuild to ???? depending on what has been done ti it. A comrable 360 can be picked up for about $200 requiring a rebuild and it too can get expensive depending on what has been done to it. Once in the car the only way to tell the difference is to check block numbers and a well trained eye may notice the hamonic balancer being slightly different. Other than that most cant tell the difference.