'99-'02 model year had the heads with 4 threads per spark plug holes. This causes a situation where the spark plugs are easily launched from the heads.

This problem is not limited to the Lightnings, as all the modular engines Ford made have this problem.

Starting with the '03 model year, Ford started using heads with more threads in the spark plug holes.

The '99 and '00 model year L's produced 360hp and 440 ft. lbs of torque and had 3.55 gears in the diff.

Starting in '01, due to slight changes by Ford (80mm MAF to a 90mm MAF and some other tweeking), the L's produced 380hp and 450 ft. lbs of torque and were now sporting 3.73 gears in the diff.

Ford also stopped using the 3.5" steel driveshaft and started putting a 4.5" aluminum driveshaft in the L's in '01.

All of the Gen 2 L's have the 4R100 tranny. A very stout unit used by Ford for the 7.3L PSD's.

Look for obvious stuff. Has it been modified and how extensively? If it has been modified, were there any custom tunes put on the truck? If so, how? Chip or flash and who wrote the tune? Someone reputable?

I'd also check how many owners the L has had. Are you buying from a younger adult or an older adult?

One thing I do is look at the engine bay. You can USUALLY ascertain if the present owner has kept the bay clean, or if its just been recently cleaned because it's for sale.

I look for this because, even though its very subjective, usually if the owner is meticulous enough to keep the engine bay clean all the time, then he has an eye for detail and will usually treat/work on/modifiy and generally take better care of the truck than someone who doesn't clean the engine bay.

Again, that's not a hard and fast rule, but I've found it to be true more times than not.

Stewart