According to a Pittman document in my possession the 12 Volt 8414 motor supplied in the P&D GP9 re-power kit has a rated stall current of 7.9 Amperes. Unless you have a flat switching layout, with very few cars per train, like Ed I really wouldn't recommend a 2A stall rated decoder.
There are a few additional things you may want to know.
The fabulously-detailed equalized P&D brass trucks have electrical pick up on only one side, through the axle bearings and multiple moving surface interfaces. On my F3s I found that to result in less-than-satisfactory electrical pickup. I installed wipers to the back side of all 4 wheels using the gearbox screws to mount them (4 wipers per truck.)
Doing so requires removing at least one side frame from the truck. While disassembled I mask off the bearing and threaded holes to keep paint out of sensitive areas, and clean/re-lube the gearbox. Reassembly is really not at all difficult if one's fingers still have fine motor control (I'm thankful I still do.)
The most elegant all-wheel pickup installs I've seen posted to the web were done by Jay Criswell. Everything he does is top-rate. Two thumbs up, Jay!
Also be on the lookout for a cracked axle gear or motor universal attachment (P&D calls the latter "helmets.") Cracking has happened on Delrin gears and drive parts throughout the model train industry when an acetyl part shrinks over time. "Hoop stress" causes the part to crack around an axle or motor shaft.
Please don't get me wrong. I'm not desiring to be in any way be negative. I really like the P&D kits.
I have 5 P&D GP7 re-power kits that I bought years ago and 7 more F unit kits to build, the first first one purchased ~19 years ago. Over the interveining years, stuff happens (wish I was 19 years younger but knowing what I do now!) Despite an occasional issue, I really like them. In my case, with Loksound V4L decoders and 2" high-bass speakers in my F3s, they sound awesome.
I'm just starting to work on my GP9s. They will receive Tang Band 4 ohm T1-1931S modules firing down, mounted through the fuel and air tanks, driven by Loksound 5LDCC decoders. The remaining F3s will get Tang Band T1-1828S speakers after milling holes in the frame for the passive radiator to fire down at the track, sound coming out of the dynamic brake air intakes and exhaust grills.
Here is a link to short video I shot on an iPhone with external stereo microphone (scene 2 to end) of an Overland brass Alco C425 with TB 1925 speaker and a Loksound V4L decoder. The last shot is an ABA set of P&D F3s grinding upgrade with V4L decoders and 2" high-bass speakers. Turn the sound up.
https://photos.smugmug.com/Tra...6O%20Ops%20-1920.mp4