19 lb injectors in speed density car

i just bought a '87 lincoln mark 7 and i just put on the stock intake, TB, and 19 lb injectors that came off of my HO mustang. this car is speed density instead of Mass air like my mustang. the stock injectors were 14 lb. now the car doesnt run well at all, not sure if its timing or what?? is there anything you have to do for a speed density car when you put in bigger injectors?(like how u need a new MAF calibrated for bigger injectors)

ok thanks for the info, i'll probably go see how much it would cost to have a shop tune it for me if they can, or else i'll just put the stock injectors back in.