"The plane should weigh approx 5-7 lbs"
150-200W per pound
Lets take the high road 200W per pound
equals 1400W At maximum, An E-Flite 52 draws/is rated at 1650W
I have a 10-11 lb P51 that uses the 52 and a 6S 5000mah lipo.
Static test current was about 78A with a freshly charged battery. Flying current at full throttle just within motor spec.
Compare that against the rimfire motor you mentioned.