Bob Foster, his power at 175 lbs worked against other light heavyweights but not against the heavyweights. He reigned as champion from 1968-1974. The more skilled was the Ol Mongoose, Archie Moore.
Bob Foster, Michael Spinks, Archie Moore came to me mind. Also Hearns, Roy Jones and Patterson if they count as a LHW.
Technically, he never fought at LHW division! If we're talking about pure punching power at LHW weight, he's probably peerless.
Curtis Shepard first then second Michael Moorer - being a HW fighting LHWs has that affect I would say out of the classic LHWs the silver medal goes to Archie Moore he may not be the brute Curtis and Foster are but the way he applies it surely counted for a lot.
Michael Moorers power carried him to HW so did Curtis Shepard’s. Wouldn’t that qualify as being greater? Despite of course Moorer being a 250lbs Wendy’s drinking monster on fight night.