Have had my 78 for 3 years.  Replaced the fuel lines, plugs,  cap, rotor,
wires.  I am intimidated by adjusting points, so I switched to a Pertronix
Ignitor. Saw an immediate improvement in drivability (like new?).  PO was
original owner & had only routine maintenance done (oil changes, ect) but the
bus was missing the egr bits.  Other than a noisy lifter on startup after
sitting too long, it runs like a raped ape.  Don't make a habit of it but, it
has suprised a few motor heads at stoplights who see the bus as an easy
target to pass & cut off. (some NOx would really hurt their egos... naaaah;)
  According to conventional wisdom, I'm living on borrowed time.   You can't
prove it by me. 
BTW- 105,000 mi  and all tinwork & seals appear to be accounted for.
(although the title says 5K original.  Now if it only looked the part...;)