Looking for but never achieved (got pretty close with my 6.5 pound Edge and Saito 125)! You are right. Let us know what size plane you are looking at and someone here can help:
YS110 = good for up to 9.5 pounds
YS160DZ = probably 'round 13 pounds
OS160 = 12 pounds
Saito 180 = 11 pounds
DA-50 = 16 pounds
OS46 = 5.25 pounds
Evolution 100 = 7 pounds
These are my guestimations for various size engines performance at sealevel...