If it's an 87 full size, it's a Grand Wagoneer. Jeep took the Wagoneer name and put it as an option package on the little Cherokee starting in 84. That's when they added "Grand" to the Wagoneer name on the full size.
Does it look something like this (but with maybe a different grill)?
If it's like that, it's the full size Grand Wagoneer.
The engine is most likely an AMC 360. It could be a swapped in Dodge engine but not likely. There's absolutely nothing in common between the Dodge and the AMC 360's besides displacement. If the distributor is on the front (like a Ford) and it leans towards the driver side, it's an AMC. The Dodge has the distributor in the back, like a Chevy.
This is what the AMC engine would look like. This is a 401 but the 360 looks the same on the outside:
The oil fill tube sticking up in the front is also a dead giveaway, as is the oil pump being built into the timing cover on the passenger side.
The Grand Wagoneer used a carbureted 360 through the end in 1991. Chrysler bought AMC/Jeep in 87 and strung out the Grand Wagoneer with the AMC engine until 1991. It used a Motorcraft 2150 2bbl. As far as carburetors go, it's pretty good off road and the alititude compensation circuit works reasonably well. The ignition is a Motorcraft setup as well. The transmission will most likely be a Chrysler TF727 with a New Process t-case that's set up for full time. Something like an NP229 that no one makes parts for.
If a Dodge engine was swapped in, there's no telling what fuel injection or ignition is being used.
That full size Jeep platform has a following. You can find out all sorts of information about them over at
http://www.ifsja.org.
