440 78 truck???

Hey all. My buddy has a friend thats has a 78 2wd truck that has a 440 in it. I am told it runs but the trans slips bad. He is wanting to sell the truck for $500. I need body parts for my 75 Power Wagon, but not sure if I want the 440. If it runs what do you think its worth? I have not heard it run yet but hope to get there this weekend. And it depends on if the body has what I need for my truck if I get it or not. Whats your thoughts???

Also easy way to tell if 440, 400, or 383...