>>Setthe valves to zero lash (rockers just touching valves).  Engine would
not
 idle, and some clatter.<<

Is clatter a clapping / clicking noise!!

Damn hydraulic lifters!
I hate those.. Remember that a loose valve is a lot better than a tight
one; don't worry about the valve noise so much (on a shot term), put Bob
.006 and maybe a bit more. Drive the van for a few miles with .006-.010 to
see if the lifter will compensate for the gap, this can take more than 30
minutes. I just finish (yesterday) a 1.6 Mazda engine with hydraulic
lifters; they took a good 30 minutes to compress back, even when the engine
was at operating temperature.

The other thing I can think is a wrong TDC timing, are you sure that you
put the piston # 1 a TDC, how do you check your TDC? Using the distributor
only is not my preferred way. Especially on a pushrod engine. All SOHC/DOCH
engine have a notch on the main camshaft gear, not our beloved Westy.

Find any kind of 1/4 dowel, wood or plastic (preferably plastic) and insert
this one in the cylinder trough the plughole just before the piston reach
TDC. (DON'T INSERT THIS ONE TO SOON, IT COULD BREAK INTO THE CYLINDER) When
the piston begin to reach the TDC and stop moving you have reach the start
point of the TDC, when the piston is starting to go down you have reach the
end point.
Try to find the middle of those 2 positions (very small) and adjust the
first piston. I know it sound archaic but believe me it works...

I know that there is suppose to be a mark on the crankshaft pulley but I
never found mine.

Just a suggestion