Cowling bumps

Now that I’ve finished the fuselage and its ready for paint, I grabbed the engine cowlings from the attic to have a look at them.  The previous builder of my project has them pretty much completed, just need some micro work.  I see also that he put an aluminum insert in one of the exhaust holes, looks like I’ll have to do the same to the other.  The two bump-outs in the lower cowling make sense – I suspect either the intake tubes or exhaust headers come close to the cowling.  I can’t understand the purpose of the bumps in the top cowling, though.

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