1987 Dodge B150 manual van with a slant 6 engine. No idea what the mfr. is on the carb (or if it's original or not); the only identifying marks I can find are the following:

on the side, and

near the base. I could also post a picture if that would help.

 

That 6R 5571 is a Carter number.

Is this it?: http://www.ebay.com/itm/CARTER-8010-...-/150546900562

 

That's it, or very close. I don't suppose you're aware of any decent documentation for that model online.

 

Nope, that type of documentation is becoming more and more rare.