I can recomend the 180...but, after Mike raises the rpm limit...
I had it on a Big Chaos and it pulled it like their wasn't anything behind it...

Break it in on Penzoil for air cooled motors then go to synthetic...
Had a upright BCM mufler (MOKI 180 is the same) and it passed the club DB levels with a 18x10 Zinger
plane weighted in right at 15 lbs....
Hope this helps...
Cause' it was happy with mine till the Great Turf God got it...