1967 Ford Mustang Accelerates poorly

1967 289 with one of the large 2 bbl carbs. The owner had it sitting for 2 years but said it ran perfectly when he parked it without storage prep or anything. I replaced the accelerator pump and it starts and idles pretty good. It just will not accelerate. Very rough. Sounds pretty lame when trying to get up some speed. If you floor it the exhaust (glass packs) sounds pretty throaty but it does not move very fast. Almost like it is trying stall or not getting enough gas. Tried carb cleaner. I can see gas off the accelerator pump and can see gas atomizing in the jets. Revs good in park and in neutral when moving. But as soon as in gear and trying to accelerate it is like it is not getting any gas.