Here's the difference in the 2 pumps, and why I asked what year we were working with. I have the M6270 on my 6-pack Dart, plug and play fuel lines, no regulator. The M6866 would fit on my '72, but you can find a non Carter at the auto store, not so much for the '69 style pump.
View attachment 1715999998
View attachment 1715999999
