I will disagree on the mechanical nightmare. Mechanically it as much as a nightmare as any modern fuel injected engine. I would change that to electrical nightmare. Every British owned vehicle I have ever had (I have had a lot) were horrible in the electronics. Mechanically they were fine. We had a joke about them, you could almost tell what day of the week they were built. Wednesday's being the best, Friday the worst.
I agree the LS motors are cheap to maintain, I have had a few of these over the years. That is not where I am coming from here. Sensors go, while cheap, they can leave you completely stranded in the middle of nowhere. Add in computer controlled transmissions and transfer cases and it get worse.
If I were to swap to a LS motor, I would get a new harness that omitted all that junk and keep it a manual trans. You get get the ECU reprogrammed for a fully manual trans. I will not be giving up the LQ4 sitting in my Yukon once pulled, it will find a new home somewhere.
Still I like the simple 2F. Closest I have had to this in all of the cars I have owned in a 6cyl was a carburated Ford 300ci. Great motor and as simple as they come, you could really not break the damn thing and believe me I tried. In the back bush, you cannot really go wrong, duct tape and bailing wire will keep you going 9 times out of 10.
The end of it is this. Freeway, ya do the swap without a doubt, you can pass safely and get out of the way faster of speeding cars. Plus you have the power for those huge hills.
Back country, I am more nervous of sensors that can break and prevent the engine from running than the speed my rig can go.
Personally I am originally from a province in Canada that is reducing the speed on some of their roadways, A good thing. Every ad you read is speed kills, yet we have Highways in the US with 75 MPH as posted limit, and it keeps going up.