BBC stock rockers arms with raised "L" on valve tip end

[opelitis1]

Going through my BBC stuff from way back and I chanced upon a couple of sets of GM rocker arms with the letter L on the valve tip end.. Is there any difference between these units and other rocker arms that have no lettering in same place??
Thanks!!
Ted

[acelr8]

Ted,The "L" on a factory rocker stands for long slot.Jeff

[jonboy1216]

x2

[opelitis1]

When did they start using these L units??  At what camshaft lift level(s) were these rockers deemed necessary??  Just came across a couple of sets of "L" type rockers and there is a difference in the rocker arm slots vs. the stock arms..
Again, wonder at what camshaft lifts did these things have to be applied, rather than cutting into the rocker arm studs??
Thanks!
T.

[acelr8]

I used them at anything .580 and up.Should have come factory on ZL1s and otherwise service replacements.Jeff

[opelitis1]

Thanks Jeff.
Ted