318 value

I recently found a 318, year, condition is unknown by the individual who has it. What makes it tempting is that it has a 340 intake manifold on it. It's complete except for the carburetor and distributor. The owner said make me a offer, but honestly I have no idea what to offer him. I don't think that he'll let me pull the oil pan either
A 340 manifold isn't all that great.

These days you have some good intake options and that wouldn't be the deciding factor for me.

In fact, I wouldn't even consider buying a 318 unless it was really something special. If you're buying an engine just be patient and get a 360. Might cost you $200 more up front but from there on you'll be playing with 20 ft lbs more, pretty much across the rpm range, almost regardless of what mods you make from then on.