Originally Posted by C.Eaton
If it's the hole under the action I seem to remember someone saying a while ago that this was the vent hole for the hammer which makes sense if think about it; impede it and the hammer can't move as readily as it would like so affects performance and all that.
That makes sense - so long as the foam allows enough air to flow through it shouldn't affect performance in theory. I would imagine AA would have tested that before fitting the foam to new FTP's.
I'll give it a test myself though just in case.