Just looked up my old thread and realized it has been 8 years since the 6BT conversion so a short update.
It still draws attention just about everywhere I go. Couple of days ago at my local farm supply store an older gentleman walked over and just said you don't see many of these around here. The owner of the store said "you probably won't see another like this one". He knew enough to ask if it is an '85, his brother has had a '68 FJ40 since college, popped the hood, etc. Another stop to drop off a hydraulic cylinder for rebuild one of the guys walked over to say "were you just bored and had to stick a diesel in it?".
I spent some time adjusting the clutch to get more pedal travel and was just about to undertake a modification to the linkage when the slave cylinder failed. A new cylinder and futile attempts to bleed it got enough clutch to drive. Took some drive time but eventually the system cleared the air and now clutch travel is fine.
The front drive shaft has developed some excess play in the shaft section and while still functional I'm going to repair it. I don't know if this is from age, the torque of the engine, or the lift.
The radiator fan lost a couple of blades and the water pump was failing but other than normal maintenance it remains as reliable and functional as I could ask it to be.
As I've stated before without question I would do it again.