Where can I buy a reliable remanufactured 318 for 1971 Duster?

There is no way I would pay anywhere close to that much money for a remain or long block. Seriously 318s are dime a dozen anywhere you look get one off market place or your buddies cousin for 50 bucks and go thru it clean it up even if it needs machine work your still under a grand and you will have a brand new motor. I started with a compete disaster 360. It was bad there was guys on here telling me to find another core! I have 350 in machine work 400 in pistons probably 400 in the valve train (cam lifters springs) 250 in the crank. And that was all performance type parts your not gonna get that in a remain or long block. You could stick with stock replacement stuff and get by ALOT cheaper! All said and done I have around 2 grand in my 360 and like I said it was performance inspired. You can build a budget 318 for less than 500 if you source the right core and do some smart shopping.
it's like some people don't even do the assigned reading before showing up to class...

he clearly doesn't want to do the work. he also doesn't have the facilities to pull the motor as he stated in the first post.

to your point of scooping up a used motor? sure, that's always a viable route but that comes with a lot of risk. you take all that time: tracking one down, hammering out a deal, going to get it, cleaning it up, doing whatever menial replace/repair work, installing it and then... something's booty. i dunno, it's got bad valve guides or rod knock or a soft hole, whatever, so now you're *** out on all that time, money and effort.

when you could've put that into a known entity.

i don't know what defines a "complete disaster" or what machine shop rates are where you are, but that sounds dubious to me on both fronts.

anyway, the guy is just looking for the easiest way forward for an economical refresh that is drama free and doesn't lay up his car because the engine is in machine shop jail for months and months.