Browsing around looking at parts for my slant 6.

I pull a fuel pump for a 72 Dart with a part number of 60577 at $XX.XX

Then I pull up a Fuel Pump for a 76 Dart and get a part number of 60576 for a different(cheaper) amount.

I pulled up the 76 Model year because thats what year engine is in my 72 Dart

Did the designs for those fuel pumps change over those years and what is the difference,is in the arm or is it internal?

No clue what changed but since you have a 76 engine put that fuel pump on it. Do you still have the fuel line routed over the head? That is another issue people have noted a lot is that when warmed up there is lots of problems with heat issues from the stock lines running over the head.

Reading your other thread I would also say the float in your carb may be causing some of the trouble...check and make sure it hasnt corroded through. Is it one of the single barrel holleys or the two barrel carbs? I have had a lot of trouble with the single barrel holleys on sixes and usually converted to the 2 barrel bbd carbs.

The only changes I can think of would be that maybe they have different outlets.

The arms have never changed.

In 1976 chrysler introduced the super six. It was a 225 slant six with a two barrel holley carb. That may be the difference in the fuel pump. In 1976 I believe the fifth character in the VIN was a "D" for the super six.

My 76 Engine has a 1945 Style Holley on it,and the fuel line is routed along the head and around the front of the water pump.

Think I might go to the parts house and request to see both part numbers first hand,just to see if there is a diffrence.

There may be a crankcase vent in the pump.