Paul,
The Datsun should be quieter.  When you tested it, did you have a shift
boot installed?  When I first drove my car w/o a shift boot, I heard all
kinds of noise that is usually muffled by the boot.  I usea boot for a
1500 Midget. 
Standard gear oil is fine.
The clutch travel is very short and abrupt.  This is my only gripe about
the conversion.
First gear:
Datsun 3.513, Ribcase 3.2 -> the Datsun is 10% shorter.  With a 4.22 diff
and 145 tires, I thought it was rediculously short.  It was too short to
build any kind of speed, you upshifted to 2nd right away.
I now have a 3.7 diff, which is a little on the long side, but still no
problem with 1st.  I now run 165/65 tires which are even smaller than
145-13s, so that offsets it a little.  I feel a 3.9 would probably be real
nice.
    Ulix                                       __/__,__      ___/__|\__  
..............................................(_o____o_)....<_O_____O_/...
                                              '67 Sprite     '74 X1/9
 |