Hmm, I never compared the 2 manuals I have, but this photo copied barely legible assembly diagram from Kenne-Bell has 27ft#s on it, so I guess anywhere in the 2 ranges ought to do ya and to be safe set them at 25. I'm guessing I must have set mine to 27 but I'm really not sure which manual I went by when I did mine, probably to hard to read KB one since its much smaller then the Buick service manual....