I've been fixing up a 1983 Westy that I got for cheap last year because it
needs major repairs to its manual transmission.  This past week I found an
'86 tintop in reasonably decent shape that was being sold because it leaks
coolant when the engine gets hot.  I haven't had a chance to remove the
engine shrouding yet, but the leak is a stream that appears at the lower
part of the shrouding under the right hand head.  I'm guessing this is a
head gasket problem.  The vendor tells me that the leak had just happened,
not far from home, and that he'd not driven it since.  I added some water
and drove it 5 miles home -- no leak at all until I let it idle at home a
while and the temp gauge was up past the half-way mark.  I killed the
engine at that point and have not touched it since.

Can I swap both the transmission and the engine (once repaired) into my
1983 Westy -- which is now freshly painted, interior restored and awaiting
a transmission.  It would be great it I could replace the 1.9 with this
2.1.  If this is doable, what other components do I need to bring along
with the engine?  Which reminds me, where is the ECU in an 1986 tintop?
Not in the LH rear corner as per my '83 Westy and not under the seat as it
is in my 1987 daily driver.  Is it the electronic device in the RH rear
corner adjacent to the air intake pipe; if not, what's that?

So much to learn about these vehicles but I've sure been having fun with
them!  My wife says I've developed an addiction.

Rick