I have 138,000 on my "86 Synchro with the original engine.  I did have to
replace one head at 109,000, but not because of head gaskets - they were
fine.  However, the left head developed a coolant weep where electrolysis
had resulted in a quarter-sized area of the external part of the head to
become porous.  Otherwise everything is running just great.

I also have some comments on tires.  I recently put on a set of the
original equipment size (205-70R14) Michelin MXTs.  After much research, I
hadn't found anything else in an appropriate size with anywhere near the
load rating of 1709 lbs (much higher than the original MXL rating of 1580
lbs).  I wondered at this rating, but on talking with Michelin Tech was
told that that was what has been determined necessary to withstand the
weight, wind loading from being so high and slab-sided, and penchant for
owners to carry ridiculous loads.  They said that much of the reinforcement
is in the sidewall in the bead area, and that lighter-rated tires would be
susceptible to failure there.  I previously had Goodyear Wrangler ATs in
27X8.50, which only had a load rating of 1528 lbs.  I also found that the
larger diameter screwed up the gearing significantly.  The van is much
happier on the MXTs, which happen to be even smaller in diameter than the
old MXLs by about 1/2 inch.