Weshennings

So I've read a plethora of resources and online pages/blogs about performing a swap of the front end on my 77, but I can't seem to figure out one thing. There seems to be a variety of front ends that can be used for a conversion to a beefier/newer setup like from the Ninja's, but I'm curious if all of these require additional work due to steering stem length... Are there any compatible front ends that have the right bearings and stem length to basically be a "plug and play" setup? I'd like to do the conversion, but I'm looking for the easiest route possible. Any help would be greatly appreciated. Most of the online resources I checked or was directed to have loads of "lists" that cover this, but don't seem to go in any detail as to whether they are actual direct fit or need additional mods.