due to the milkshake looking gunk in the valve cover i'd say go with a different motor. they can be found everywhere since Chrysler made so many of them in the '80s & early 90s.
you can turbocharge it, but not the existing engine. the existing engine would probably have too high of a CR, and the block doesn't have the turbo oil drain tube in it so you'd either have to drill & tap the block for the tube or weld a drain tube onto the top of the oil pan. the main reason however is that the NA engine doesn't have the strong internals that the turbo engines got. the Turbo engines for example came with forged rods (depending on year), and of course lower CR. the Turbo II even came with a forged crankshaft. however, the cast crankshafts are plenty strong IMO and they weigh less. in '89 the 2.2/2.5 block was changed/strengthened. '89+ engines are known as the "commonblock" because the 2.2 & 2.5 block were now identical; meaning you could put a 2.5 crank into an engine that was previously a 2.2L. stay away from the '84-'87 Turbo engines because they had a crappy suck through turbo design and are very tough to intercool and the log intake manifold sucks. in '87/'88 the Turbo engines were changed to blow through, so adding an intercooler is easy and the intake manifold is much better (though to be honest it still sucks lol). these are definately low end torque motors, not high revvers (with exception to the Turbo III engine found in '91-'93 Daytona Iroc R/T and Spirit R/T which are very rare).
i think the easiest way to turbocharge it would be to find an '89 donor car with a 2.5 Turbo I engine (Shadow, Lancer, Lebaron, Daytona, Caravan, Spirit etc). the motor would drop right in but you'd have to use the '89+ commonblock motor mounts (you should really get new motor mounts anyway). the Turbo I engines came with a small Mitsu TE04H turbo, which is REALLY small, but it does the job and it does spool very quickly. you could always upgrade to a T3 from a Turbo II engine later on (bolt on), or a T3/T04E hybrid which would also bolt right on but you'd have to change the oil/coolant lines going to/from the turbo because the lines going to/from the Mitsu turbo are very different. as far as electronics go, your best bet would be to do an SMEC conversion, which would probably require ripping out the entire engine wiring harness & current SMEC and then just changing some pinouts on the bulkhead connector on the firewall. you can run without an intercooler (Turbo I engines didn't even get an intercooler from the factory) but obviously you'll get alot more power with one and a van has plenty of space for a big FMIC. Turbo II engines were all intercooled from the factory. there is also the Turbo III engine, which is the DOHC 16-valve Lotus head engine. that would be ALOT of work though and finding parts would be really tough/expensive (my brother is currently doing a TIII swap into his Shelby Lancer). there is also the Turbo IV engine which is really just a Turbo II engine with a Garrett VNT T25 turbo. finding a Turbo II, Turbo III, or Turbo IV is going to be tough. however finding an '89+ Turbo I would be easy so i'd say an '89+ 2.5L Turbo I engine is your best bet - easy to find, easy to swap and parts are cheap. fwiw, the Turbo I engine was 2.2L through '88, and for a heavier van i would really stick with an '89+ 2.5L TI.
the first mod would be to get at least 2.5" (or better yet 3") mandrel bent exhaust. that helps ALOT. then get a $25 grainger valve MBC and crank the boost to 14psi (if you have an intercooler) or just 10psi if you don't. even then the van would fly. after that start looking around at http://www.fwdperformance.com
. they have alot of parts/upgrades available and they cater only to the Turbo Dodges. the owners of those sites are on the turbododge.com forums, so they are always there to help/answer any questions. my brother and i have bought alot of stuff through them and have always had good dealings with them.
- lots of pics there of my '89 GTS and Turbo II engine on the stand and alot of other pics as well. my brother has pics of his cars at Shelby Lancer
, Omni GLH
and Spirit R/T
there are quite a few Turbo van owners on turbododge.com that could help you out. lots of helpful members over there; and you'll probably find out right away that turbocharging your van would be alot easier & cheaper than you think
due to your van likely needing a new engine anyway, i would definately do it!