Dear Dave
I suggest that it is the pump.  If you can get a flow meter that will really
help.

I would bet the pump is cavatating at the highter RPM.  Without the
thermostat it cant build pressure to over come the cavatation tendancy.

This used to happen to many racers I knew.  They would remove the thermostat
and have a heating issue.  Many thought you needed to slow the water down as
it flowed through the block.  That never made sense to me.  Myself and a few
guys put flow meters on the system and noticed flow would drop or stop at
certian RPMS.
theory was cavatation.  Put a under speed pully on and it got better.  What
really made the differance was putting on a smooth, well designed impeller
vane, that did not induce cavatation at higher RPM and flows.  Impellers hav
a flow rate they work over too.

Quick test might be to put a restriction in your line to see if you can get
the system up to temp.

Eric


Problem 3: (THE BIG PROBLEM) My coolant doesn't seem to be flowing well,
despite the fact that I have no thermostat and have welded the bypass
passage in the pump housing.  I ran for almost an hour at 3000 RPM with no
apparent problem.  Going up to 4000 RPM after that the coolant quickly
overheated and boiled over.  Surprisingly, the radiator was just luke-warm.
Now I am really worried.  I remember that someone else recently was having a
similar problem but I lost track of how it was solved.  I am considering
some possible causes.  A) My AN-16 hose (engine to Rad) maybe is just not
big enough - unlikely because the fitting on the rad doesn't even get warm.
B)  the Water pump sold to me by Adkins is really for a 3rd gen and is
running backward. - possible because the outlet side of the rad seems to get
warmer than the inlet side, but only slightly maybe and it is closer to the
turbo.  C)  I have a flap of rubber partially blocking the outlet hose.  D)
The pump just refuses to properly prime itself.  E) Maybe the thermostat
bypass passage is not properly welded closed. - can't see it because of the
welded plate, will have to look with a dental mirror.  F) ???? any input or
other ideas?

Dave Leonard (still rather be working on these issues than shaping that exit
duct)