my '94 F150 XLT SuperCab with 5.0 and the e4OD (it this one in the same as the 4R70W??)just turned 125k, the only trouble is the rear main seal on the engine started leaking around 120k.
I have been around the famous small block Ford engine since I was 16 years old-back to the 260, and 289, and I agree they are not really a truck engine, but will do what the truck is designed for in any given case.
Someone said they most likely would not replace the engine in their truck, I assume that the cosmetic condition of the truck dictates this, my 1994 is all but immaculate and I keep it that way, I will most likely run the current engine until it just won't go anymore and then put a reman. long block in it.
I plan on having the rear main done soon and also having the transmission serviced and both front and rear seals in it replaced while its out.
I figure around 200k I'll replace the timing chain, front seal and water pump.
I have recently been told by my local independent trans shop that the 4R70W is "bullet proof" execpt may be the torque converter which has a clutch inside it much like a manual trans clutch and IT wears out, he says mine is fine with 125k on it, and I should just drive IT until it breaks and have him rebuild it for $1800.

 

Speaking of the engine it self. We've had 4- 302s and three of them have gone to 250,000 or more. The reason we usually got rid of them is because of all the little problems electrical. But mine has 108k on it, and no oil leaks. I change the oil a little excessivly, about every 2000-2500 miles, but it works great, and should continue to work great for a long while.

 

MY 302 on a 1992 Ford ran strong until about 225000 miles. Just needed the EGR valve fixed and it ran fine after that. It was kept up on tune ups though. Every 3000 miles tops.