Thunder Power 4s 2800mah 25c will get the job done. You might need to trim the prop to 11.5" but do try it at the full 12" first. I trimmed mine down because the corners were too soft. Big difference by losing a  mere 1/2"!
Bob

Hey all, I have a E Flite Power 25 probably around a 12X6 prop going in a Legacy 40 type stunter, it's a tight space where the battery is going so a 5s won't fit, please about what MA ratting will I need?
thanks.

Dwayne - I have flown a similar setup for two seasons - Hacker A30-10XL (same specs. as the E-flite 25), Castle Ice Lite 50, Hubin FM-9, APC 11x5.5 pusher, and Zippy Compact 4cell X 2700 mahr, in a 49 ounce much modified ARF Nobler.  Four cells with a 900kv motor is fairly standard, and produces plenty of power.  Zippy Compact will just fit in the narrow Nobler fuselage. The challenge is to creating adequate air flow around the battery. I have used the 12X6, but prefer the 11X5.5. The 2700 mahr battery is 80% exhausted after 5:30 air time.  The two props consume about the same mahr when flown at the same airspeed.  The one inch increase in diameter from 11 to 12 is offset by the 1000 RPM reduction due to the higher pitch.  The increase in pitch has only a small effect on power required.  Keep checking this forum, the info is here.

Thanks guys I have a couple Venom 3200 so I guess they are a bit overkill but will give em a go. Thanks again.