Which 60 do you have? I have the 60 II with a CL crankcase, meaning no holes in the sides of the exhaust port. I also have a 60 III with a G8 carb. The latter is such a classic it has been re-issued by Enya and lots of people here have posted about what a great engine it is for its weight. Then there is the 60X, a whole different animal, and others. So you need to know what you have.
The 60 II and the early 60 III types for RC had holes in the sides of the exhaust for an exhaust baffle. The problem is it weakened the metal. I got a big box of old Enya 60 parts and there were four broken crankcases that all broke where the holes were. One was still intact, and broke on my test stand. Then I found a 60 II CL case on ebay with no holes. Now it is a good engine.
Jim