It depends on the purchase of the outhaul.. I don't have a block on the clew itself but we have a 6:1 internal purchase. On smaller boats with a singlepart external outhaul (like the above example) a good bearing block should reduce friction.
1984 Fast/Nicholson 345 "FastForward"
".. there is much you could do at sea with common sense.. and very little you could do without it.."
Capt G E Ericson (from "The Cruel Sea" by Nicholas Monsarrat)