I tried a few tips and tricks from a thread on AS,,I think it was Andydodgegeek started it a couple years ago.
(I use an old Foley Belsaw grinder.)
Full skip chain, knocked the rakers back and thinned them, and took a little out of the tie straps on the top edge, think a figure 8 lying horizontal, and changed from 32 degrees to something like 22 1/2 degrees.
^^these details are from a couple years ago^^ and may not be accurate on the angles.
Anywho,,24" b/c combo with the mod. chain on an approximately 20" pignut Hickory and was making like 10-12 seconds cuts,,very fast to this firewood hack.
It dulled very quickly and was the end of my modifying chains.
What I took away from the thread and my playing around was, making room for the chips to clear is the joo-joo in making a faster chain.
I dunno.