AJ, the whistling during warmiup may be due to a leak in your aux air valve
circuit(84 had them)  as for the engine...My 84 has been meticulously
maintained since new w/ all oil and coolant changes.I have orig.heads and
head gaskets at 220k mi. but Im an exception rather than a norm.I have
travelled w/o regard from San Diego to Calgary A.B. in Dec./ 5 years in a
row.To Alaska and across the Mohave desert pulling a trailer in Aug for 7
tears.Ok Im a gambler.........I have had other annoying breakdowns..but no
water problems...mind you, I custom tuned my engine(believe it or not,
Canadian truckers were talking up a storm on CB last December when I blew
them off climbing the trans Canada out of Calgary to Banff with 5 people and
ski gear travelling 85mph), and installed a custom lower t/stat 160 deg.so my
engine has run cool from the gate.I would suggest you try to get the service
records from the prior owners  and have someone check out the engine
thoroughly(compression,scope,co% etc.then check the coolant w/ a color dip
indicator(for exhaust gases) or pressure tester, or have your mechanic check
the coolant w/ his HC sniffer. If this is ok I would probably chance
it....but other members may disagree w/ me on this....Hey life's a risk.
 What say you Dennis?

Good Luck

Ed Berroth
84 Westy Wolf
87 Stinkcrow