Where did you get your new motor?
My 4.7 has been running smoothly. Has 135k on it with 4.5" lift on 35s, yes no hemi, but she still moves and is fine with me!
I'm gonna guess powertrain products. From what I've read it seems they fix the weak points with these motors
I have the 3.7 which is basically a 4.7 with 2 cylinders chopped off (I know the differences between the two aren't that simple, but they're similar alright). I've put 50k miles on it since I bought it, I haven't been stranded yet. Not even a check engine light. (Which I figured out recently doesn't work anyways. Irony).
Its VERY noisy and I'm looking at a coolant leak from a hose and possibly an oil leak or oil being burned. But I must say I'm pretty sure this truck was abused pretty heavily over the 106k miles before I got it. A former fleet vehicle with zipties and duck tape fixes?? The bumpers (which weren't chrome as listed on the build sheet), mismatched body lines, and a VERY tweaked frame leads me to believe it was in some sort of accident as well. With all the issues and neglect I see on the truck around it, I'm sure they didn't treat the engine much better.
But with that said it's still going and hasn't ever left me stranded. I'm sure if you keep it maintained it'll last you for a good while. I know of a couple of people around the internets that are/were over 300k miles on their 3.7s and 4.7s. It won't be a powerhouse and will also be a gas hog, but enjoy it for what it is. Normally I'd say "get a hemi" but a whole truck for free? I wouldn't care if they replaced the engine with an oversized golf cart battery, you wouldn't hear me complain lol
As someone else said earlier, at least its not the V6 lol
EDIT: I would like to point out that exactly 20 hours after posting this my truck now won't start in my driveway due to DTC 127E (fuel pump issue). I should've knocked on some wood