Right now I have the L134 Go Devil Flathead - whopping 65 HP at the flywheel from the factory.
When I got it a few years ago I had it rebuilt and the machine shop said 0. 060 over is all it can take before re-sleeving so maybe that added 0. 5 HP.
I can do 55 downhill with a tailwind. Most times, it's 2nd gear 25 mph up any hill.
Seriously, this is a pipe dream for me now since house mods take priority now. The only other things I want to do is swap my front drums for Chevy 1/2 ton 4x4 discs (waiting on the workbench) and build a roll-bar for it (need friends with tubing bender that know how to weld).
03 2500 4x4, HO, 6spd, ARP, PDR cam, HD springs, dual CP3, SBC 3600DD, GT3788R over GTX4202R, Flux 4, UDC, ISSPRO Performax, Thuren goodies.