Stuck Valves

["Mike Brinker" <Mike.Brinker@mfasco.com>]

After doing my initial Run In on my TR6 motor, it began to run extremely
rough with some back firing.  When I removed my valve cover I notices 3 of
the valves were stuck open (in the down position).  why would this happen
and what is the cause?  I have a newly rebuilt head with all new valves and
guides.  Oil pressure is good 85 - 90 lbs and I primed primed the engine
with oil before my first time start up.  I used a special tool that allowed
me to turn the oil pump and circulate oil through the entire engine without
moving a piston or moving a valve.  Now it seems I have to pull off the head
and take it back to the machine shop.  Any ideas why this happened?  What
will prevent this from happening again!
Mike