engine condition?

I have a used 96 4.0 engine I am thinking about swapping into my 92 xj. The engine is supposed to have only 55,000 miles on it.Whether it does or not,i got a heck of a deal on it. Is there any way i can tell what condition the engine is in without taking the head off? I really don't want to get into it that deep. thanks for the ideas....Ben

Do you have access to a leakdown kit? That's the easiest way to check - and I'd probably run the first batch of oil about 500-1000 miles, and cut open the filter and inspect it.

A leakdown test uses compressed air (two gages - one for source pressure, one for cylinder pressure) to check the seal of the cylinder and valves. It's easiest to just pull the vavle cover and rockers to seal all the cylinders (you still have to go to TDC or BDC to do it, but it's simpler than doing the test with the valve gear functional, you'll have to find TDC compression, ...) That will also give you a chance to clean out the top end of the engine. If you see sludge under the valve cover, pull the sump and clean that out as well, and inspect the bottom end while you have it opened up (pull the #2 and #6 mains and a couple of rod caps to check, I'd say.)

If you're not sure, Google <Leakdown Test> or <Cylinder Leakdown Test> to get an explanation. Note that a compression test will also test the seal, but the leakdown test will also enable you to pinpoint a leak - while a compression test will not (you also need a starter motor to do a proper compression test.)

would a leak down test be accurate on an engine that hasn't been ran in about 2 years?

A leak down test will tell you if the cylinders seal properly, which is a very good indicator of the condition of the cylinder walls and rings.
Was the motor properly stored?
had some oil been squirted down the plug holes to keep the rings from rusting to the cylinder walls?
Hate to say it, but you really should take a look in there.