I went from stock MAF with GT40p heads, trickflow intake, heades, stock injectors , 3.73 gears etc and then added a 73mm maf meter. It was night and day difference. Think about it, you are going from 60mm to 73mm , thats 18% more air. The stock air meter is the main reason going from 88 to 89 years, the 88 was faster because it didnt have the tiny MAF meter inbetween the TB and filter.