will i run lean with this combo, or can i pull it off?

Without an wideband and without knowing what your final numbers are going to be, it's hard to say. I think that you're going to be pretty close to the border if what the 19s can do on a N/A car with no way to ramp up the fuel pressure through the RPM range. My thought is that even though an adjustable fuel pressure regulator will allow you increase pressure, that you'll be doing it at the expense of idle quality and low end drivability. I think that by the time you get the fuel pressure set high enough to accomadate demands in the upper RPM ranges, that you're going to be over what the computer can compensate and lean out for at the bottom end. If you don't mind being rich at idel and low RPM then go for it. Especially if it will be just a temporary measure. You're still going to need a wideband or at least a dyno sniffer so that you know where to set FP to meet the demands of the combo at redline. You'd probably make best power in the neighborhood of 13.2 - 13.5 AFR with that combo (just a guess) but I'd limit it to around 14.1 to try and stay as close to stoich as I could for the rest of the RPM range at part power settings. With the 19s and normally aspirated, I think it's going to be a balancing act.

19's should be adequate, as long as you have an upgraded fuel pump and AFPR to supply enough fuel. Go to fordmuscle.com and search their project car Green Machine II, they ran 19#s with a Typhoon intake and TFS heads and went 12.1x in the quarter.

19's are pushing it.

i agree with putting it on a dyno. thats the only way to be sure