Best mod is a 5-speed transmission.  I got mine from Weddle Industries, Santa
Barbara, California.  This gives the old Westy 4 gears with 5% more power
(lower gearing) and 5% overdrive in 5th.

Fourth (4th) gear goes out to 65 mph comfortably and can go to 70 mph.
Without a loaded down Westy, I can go up the grapevine, California's Interstate 5,
in 4th gear slowing down to 60 at some places.

Fifth gear (5th) gear allows cruising at 75 mph on I-5 and can go to up to 85
mph at about 4500 rpm.  All this on the stock 2.1 liter engine.

George
'88 Westy