Note the huge difference in venturi size. Remember, a little means a lot in this regard. The square inch area increases dramatically when increasing a "round hole". This is why a 2½ exhaust pipe can flow a LOT more than a 2¼ exhaust pipe.
The 1976-78 Chevette 1ME on the left, and a regular Rochester 1ME for a Chevrolet 250 6 cyl.
Note the huge difference in venturi size. Remember, a little means a lot in this regard.
The square inch area increases dramatically when increasing a "round hole". This
is why a 2½ exhaust pipe can flow a LOT more than a 2¼ exhaust pipe.