Really back in the day, a vehicle with more than 80,000 miles on it was acknowledged to be worn out. And my favorite long term mechanic told me that Ford flathead 4s and V8s could stand new rings and bearings every 40K miles. He counted on them to make his living.

When my wife and I went out to buy a "new" truck we ended up with an '07 F150 with the two valve 4.6. You really have to twist it tight to get it to move out. So it's got overdrive and a small modern V8 and the first 600 miles it averaged 14.7 mpg. The second trip averaged 14.74mpg. I never get 15mpg either in town or on the freeway. Thirsty.

I was really disappointed to find out I didn't get a higher power 3 valve engine. But then i started reading Ford truck Enthusiasts online and see that while the 3 valve 5.4 has a lot more power, at around 125K miles it needs basically all the valvegear and timing equipment replaced and the only quality parts are FoMoCo and will set you back about $1500 for the parts. Plus they have real spark plug problems you may have heard about.
The message is don't feel so all alone.The modern small V8s eat gas and money. The GM LS engines don't have the valvegear problems but once again the 4.8 has to be revved to the moon to put out any power. The larger engines don't seem to have those problems.
For my 4.6 the key seems to be use only factory parts, and keep the oil fresh and clean.
R.