I have a very similar set up.
Stock bottom end
GT40 3-bar heads with smoothed intake and exhaust ports
Explorer upper and lower - internal EGR style
BBK 70mm TB and EGR spacer
C&L 76mm MAF (I had a 73mm on it and it doesn't seem to have made much difference)
C&L cone filter connected to hood scoop air feed.
19 lbs Explorer injectors (they have 4 nozzle holes vs stock Mustang single hole)
1.7 RR
Crower 15512 cam (
[email protected] 222/228, adv. dur. 282/286, lift with 1.7RRs .527/.544, 112 LSA)
MAC equal length shorty headers
MAC 2.5" Pro-Chamber with aftermarket cats added
MAC 2.5" Pro Dump mufflers with turndowns removed and 2.5"
Flowmaster LX tailpipes
Innovate dual wideband (DLG-1 kit)
I'm a factory AOD car with AOD still in it (A9P ECU).
I have an Anderson PMS hooked up but not tuning. I am using it at this point as a monitor. What I have seen is at WOT, around 5000-5500 rpm, I was at 95% duty cycle on the injectors (wideband was showing 12.8-13.5). I think my horsepower level is 320-350 HP at crank (no dyno test to prove). Other than the calibration tube in the MAF, I have no tuning done to the system. Watching the widebands, the system seems to be behaving with no leaning out or over rich situations when driving under load.
I have just changed to 24 lbs injectors (because of the 95% duty cycle) but have not been able to test whether this has made a difference in performance. It does idle and run very well so far. Again only a custom sized calibration tube for the MAF to make it run. Hopefully some tuning in the spring/summer.
Depending on how you are planning to use your car, 19 lbs injectors for a street cruiser (that will not see high RPMs often) should work well with your combination and can simplify the conversion to MAF (stock computers, harness and MAF).
Just my personal experience and my 2 cents on your combination. Let us know where you go with it.