looks like nobody wants to answer the question so I happen to have a answer for you for a 60 size you can run the Zenoah G-20, or in my case a BCMA 26spe engine in my TF 60 size P-47 T-Bolt I am building ,Brillelli engines have some smaller gas offerings there are lots of small gas engines for 60 size panes you do not need to get a giant scale for gas.
what you do have to do is have throttle management mostly because these engines are a little much for these planes I kind of like a little extra power myself check out the review of the Hangar9 hellcat on RCU the guy put a Z G-20 in that one seems fine to me, here are some photos for you of my progress on my TF 60 size P-47 great model to build been at it for just a little while now.
the weight is about the same as a 120fs for the BCMA check www.bcmaengines.com they run well.