general rules apply to keeping a k car running right....tuneup items, quality fluids (preferably synthetic) flushed at regular intervals, etc.
there were a few design changes over the years that improved durability and performance.
if you have a slider camshaft, a roller camshaft that was phased in in 1988 (most 2.5's and 2.2's got it mid year) will seriously reduce friction. make sure you grab the matching followers from the engine that donated the camshaft with the actual roller bearings on them. and don't try to use a slider cam in a later cylinder heads....they deleted the oil squirter passages some time after the cam change and a slider cam will burn out very quickly without extra lubrication. most aftermarket performance cams old school slider type, so plan hop ups accordingly!
a 2.5 makes more power than a 2.2 for about the same gas mileage. especially nice when coupled with a 5spd. i don't like the 2.2 with an automatic.
there are different eras of electronics. and the turbo engines some differences in the wiring (multi-port injection) as well as more circuitry in the computer:
1986-87 = Logic and Power module (one module under hood, one in front passenger kick panel)
1988-89 = Single Module Engine Controller (combined the L & M into one under hood unit)
1990-91 = Single Board Engine Controller I (both functions on one circuit board)
1992-95 = Single Board Engine Controller II (not compatible with SBECI)
As for head gaskets......use Fel Pro on your classic muscle car, but NOT on a 2.2/2.5. the consensus in the performance community (turbododge.com and turbo-mopar.com) is that they are no better than the factory chrysler gasket. if you do a HG job, reach for the heavy duty unit from Mopar Performance:
P4452005 Carb and Turbo I
P4452006 Turbo II & 2.5 Turbo I
remember that the 2.2/2.5 have siamese cylinders (no room for water jackets around cylinders). most turbo engines and 1991+ tbi engines should have cross drilling to route coolant through the cylinder head and block. definitely a nice feature if you live in a hot climate or the car sits in traffic regularly.
also check out
www.thedodgegarage.com for some interesting reading. mostly about hopping up turbo 2.2/2.5 engines but some the tech can be applied to naturally aspirated engine as well. and there is a page devoted to hopping those up as well.....other tricks i like are opening up the bottom of the oil pump pickup (so you can see more of the screen). that will cut down drag and make it easier for the oil pump to suck up oil over 3000rpm. and port matching the oil pump to the block (pump has an oval hole and the mating hole on the block is a smaller/round = rough edge causes parasitic drag) which is supposed to be good for 5hp as well.
another item that can cause problems is the
Be aware in the base of 2.2/2.5 distributors there is a plastic disc that holds the pickup shutter wheel in place. They tend to loosen with age and will cause your car to misfire and idle poor, always a good idea to check it when doing a tune up...
that is straight from the dodgegarage!
there is a ton more but that should get you all started. i love my k wagon, but LUST after the performance variants and spend a lot of time on forums devoted that stuff.