I have a saito 100 in my pulse 60 and love it. I will prolly never have another 2 stroke glo engine agian. The os ultimate series has a built in fuel pump and is not really needed for a pulse so I would save the $100 if I were you and go with the surpas or a saito. I was gonna go with os but I liked the lighter weight and extra power of the saito. Not that it matters for the pulse but I was thinking ahead incase I wanted to use it in a 3d plane later down the road.

If there recomending a bigger engine then the os 70 a saito 82 would prolly be perfect and it weighs pretty much the same and has same mounting size. A ys63s would really be nice on it but they are a little harder to get setup properly.