No problem. This issue is solved by true "Hot Rodding" techniques! Use your head and follow along below with some imagination. The problem being no Dakota is listed at Summit as having a V8 until '93.
The collector size should be listed by the maker (and/or seller) of the header.
Look here at Summit. As said. Earliest year for a V8 would be '93. If there are changes, I am unaware. But it may, repeat, MAY WORK.
https://www.summitracing.com/search/part-type/headers/header-style/shorty/drivetrain/4wd/year/1992/make/dodge/model/dakota?N=4294924068+4294924002+4294948686
