Westy
Adventurer
There is no reason to replace the birfields with Chromoly (Longfields) on an 80 series Landcruiser if you are not running 37" + tires. You will also find that many of the aftermarket STOCK birfields are of less quality anyway than the factory units that are likely still sitting in the axle. They are plenty strong enough to survive under an expedition 80 series.
It is not unheard of to hear of early 4runner/Pickups running 37-40+" tires on a stock, yes stock 80 series axle with stock birfields; sucessfully. They are significantly stronger and bigger than the mini truck/4runner 79-98 birfields.
Replace seals, felts, and repack the birfields and they will be good to go for the distance. Consider using the new Marlin HD seals as well if you rebuild the axle.
It is not unheard of to hear of early 4runner/Pickups running 37-40+" tires on a stock, yes stock 80 series axle with stock birfields; sucessfully. They are significantly stronger and bigger than the mini truck/4runner 79-98 birfields.
Replace seals, felts, and repack the birfields and they will be good to go for the distance. Consider using the new Marlin HD seals as well if you rebuild the axle.