Kent,
Your wife is right on! You can use the Westy for camping & all sorts of fun, as a counterpoint to your 914s. They actually drive better than one would expect from a tall brick on wheels!
I don't know if you mean it's running but needs an engine, or is a roller at this point, but if it's a runner still, you could take it to my longtime mechanic in Huntington Beach for a PPI, & he's still taking Vanagon customers - just tell him about your plans for a Subie transplant. He has some customers with Subie-Vanagons, so he & his guy Larry will know them too.
The 86's still had the older & less desirable 1.9L WBX, & so it's a good candidate for a Subie, but ask others with them about their reccos for best engine to use. Since the WBX Vanagons are already plumbed for water-cooled, & they were designed from the start to be a WBX - even though the 1980-83.5 ones used the 2.0L ABX until the 1.9 WBX was ready, & they had water-cooled diesels too.
Like the 914s - look everywhere for rust - check all lower panels, belly pan, around all windows & doors/hatch, battery boxes under both front seats & engine bay; as well as DAPO hacks that would cause you grief later on - and electrical & harness amateurish hack jobs would top that list for a no-go. The suspension & running gear would be another area - including at connection points to the unibody - but bearings, bushings, shocks are still available.
Along with the Subie upgrade, you may want to consider doing a GoWesty front big brake upgrade (requires going to their or other 15" or 16" wheel package - IIRC the 15" still fits the spare belly pan, but not the 16", but ask them), & using the rear disks off of the Subie trans or donor, since the stock rears are drums.
Another option to consider, is getting a GoWesty upbuilt 1.9L or 2.1L to as much as 2.45L or 2.7L with close to the same HP & TQ as a Subie 4, but with 2 advantages - less mod work & a 4 yr/48K mi warranty - but do the full cooling refit as well in order to not lose coverage for a coolant part failure. GoWesty can give you the parts/prices for the whole bundle, & I'll bet that it's not far off of a Subie conversion counting everything needed for it!
https://www.gowesty.com/shop/vehicle-parts/...-engines/176?v= Because the Vanagon & Westfalia OEM parts are getting scarce & much of the used stuff is trashy, I'd not go for it if it's missing a lot of the camping gear & other fittings. make sure that all the cabinets, stove, fridge, sink, water tank, hook-ups, lights, LP system/tank, etc. are present & operable - even if you plan to upgrade some (LP tank is a common upgrade). Check the pop-top & luggage rack & all gear for it, & that it operates (replacement skylights & seals are still available, but the best are expensive).
For parts, check VW Bus Shop in Germany 1st (usually 5-10 day shipping to USA), then GoWesty, Van Cafe (now in CO), Bus Depot for parts, & there's a CO shop that specializes in Subie conversions & parts which can give you an idea of costs for that option. If you need links, then I can send or post them.
Lastly - anything with a pop-top is the highest value Vanagons, & a well restored full camper Westy would easily be worth $50-$70K+ when you're done - even with a Subie swap, or with a GoWesty or other rebuild/upbuild WBX that's not original. & As with our 914s, the Westy values have continued to go up, & even held flat during the 2008-10 "Great Recession". So IMHO, the Westies are a better economic choice for restoration, than are most 914/4s - which was partly why our OO `88 Westy moved up in front of my 73 914-2.0 when it got clipped in a minor accident in 2013.
Check out the GoWesty recent sales for #4-5 Westies:
https://www.gowesty.com/vehicle-sales-history.php So an OVR will be advised after your resto/upgrades in case of accident/damage:
https://www.gowesty.com/product/vehicle-val...of-value-report GoWesty also has a pretty good library on the major quirks, issues & how-to's for them:
https://www.gowesty.com/library.php .
Next thing will be that your wife will want you to find a vintage Eriba Puck to take her to vintage trailer rallies with the Westy towing, as mine did!
Click to view attachment But don't despair - if 1950's VWs with 25 HP & this 356 can tow them, you can also put a hitch on your 914 & tow it too!
Click to view attachment Click to view attachment .
Shoot me an email if you want to talk more about it this weekend, & I'll send you my cell #.
Good Luck!
Tom
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I said no because I need to get rid of one project before taking on another. Mind you, this comes from a guy who's been spouting off about downsizing so he doesn't leave this mess should he unexpectedly depart this planet suddenly. 
I tell my wife about the call and she tells me that I should do this. What should I look for when checking one of these out? Known gotcha's? Price ranges? Drive train will be converted to ...................drum roll pls................Yes, Subaru so I won't need VW engine or transmissions estimates. TIA, Kent
I can't help much on what to look for before you buy since mine doesn't run but here are some folks from my Vanagon thread who have them:
