Hi - I'm working on my farm's chevy 87 c-70 w/ 366 v8 (which came out
of an early 1970's era truck). The motor runs and has good oil
pressure (according to the gauge) but there is no oil coming out of the
pushrod tubes and the valves are very noisy as a result.

What would cause this to be? There is only a little trickle of oil
coming out the pushrods for the number 1 piston (the front one on the
drivers side), none at the rest. I'm noticing it now because I just
had the head off the drivers side to fix a broken exhaust valve and
once it was all put back together the noise was terrible; before taking
the head off there was no noise but still hardly any oil coming out the
tubes.

I pulled the oil pan off and the pump looks fine - no plugged screen or
damage. I also pulled off the bearing cap on a couple of the pistons
and that looked ok - no visible problem. A local motor shop told me
that if the cam or cam bearings were bad we might have oil at the back
(closest to firewall) tubes but none torwards the front. SO - I'm at a
loss.

All and any help is greatly appreciated.