71 340 engine value

You'll want to know what pistons were used in it- how much it was bored and what CR pistons, how much the crank was ground, if the rods were reworked or replaced, what brand parts were used for it, what was done to the heads- and how they started. Another common problem to look if it had/had fixed is the lifter galley cracks.

Like they mentioned- 3-5 hundred is normal for a good block that needs minor work and it will generally be a '72 or '73 if it's not had lifter galley cracks, holes in the walls, or need to be bored over .03. A motor needing everything in the heads and a complete rotating assembly rebuild isn't going to end up being cheaper than that if you have to piece-meal everything.