Recently purchased a 1998 crate engine meant for an F150 truck.I want to put it in my 1999 Expedition, apparently the head design/intake is different.Can I use this engine? Is it a matter of a computer change? Or am I euchered..

 

I'm trying to do something similar which is replacing my worn out '98 5.4 with a '00 5.4. Keep me posted and I'll do the same.
Mike

 

The motor will bolt in but you'll be moving backwards as far as horsepower is concerned. The pre 99's have crappy heads and intake manifolds. I helped my buddy install a 99+ in his 98 and it more or less was a simple bolt in swap. The only thing that wasn't really a plug and play is that the 98's have a weird electric valve in the intake runners that the 99+'s don't have. The fix was simple, just don't plug in the valve and no codes or issues at all.

The only issue he's had is a few months after putting in the new motor he got a code for his rear O2's saying the cats weren't working very well. I'm wondering if this has to do with the newer motor running off the eariler motors pcm. We did the spark plug fouler mod on the rear O2's and all has been well since.