72 Duster help

Is there a way to ID if an engine is a 340 or 318 without looking at the block ? The fender tag is missing, and the VIN says 318, but the guy selling it says he does'nt know for sure, he took it in on a trade for a motorcycle. The car is in Michigan, I am 4 hours away in Wisconsin, so it's not like I can go look every day, but the owner says I can put it on his rack when I get there to look it over .

I have to wait till I see the car to ID the engine, trans, and rear end, I hope it is a 340 . As far as the trans goes, I know a 727 is the way to go, and a 8 3/4 rear end is too. I am interested in this car a lot, only have seen pics and a video, but the interior is a 9 out of 10, and the paint he says is a 5 or 6 out of 10. The car is from South Carolina. If it is a 318, and not a 727, I still would be interested " IF " it is as nice inside and out as he says. Looking for a project car for my Son and I . Last question, how do we ID the rear end, to determine what it is? If these sound like simple questions, well we are noobs, be gentle .