I'm looking for a wed site that sells cheap dc forklift traction motors or dc electric motors or a salvage yard.

What size lift capacity? What is it you want to do with it ?

What size lift capacity? What is it you want to do with it ?
I was thinking about turning my 72 GMC pickup truck into an electric vehicle but not sure of the size of traction or electric motor I'll need,also could the alt be used to charge the battery's

What your looking at doing is best done if you have been there before. What you might want to do is a little research and look at some of the plans and videos out there for building an electric vehicle. As far as the power plant goes you might want to ask around at forklift shops and see if they have ones they are going to wreck out for parts. So long as the electrical system is still in tact then you could offer to buy it at a low price. Let them keep the mast and couterweight. That way you will know exactly what system you are dealing with.

There are many control systems out there as well as the newer ones actually run A/C motors. As far as can an alternator charge something that is going to depend directly on how much the control voltage is that your going to be using. Typically 36 or 48 volt is the most common in large forklifts. Depending on the age of the system you use you may have the option of regenerative braking (it turns the drive motor into a temporary generator and stores the electricity back into the battery while slowing the vehicle down).