Looking for some guidance.

Hello everyone,

I have been looking around trying to find some information on an issue I am having with a recently rebuilt 340.

I have not even had an opportunity to break it in yet, because when if fires up it has great oil pressure cold. Once it warms up the pressure drops to where it will register pretty much a zero at idle on a mechanical gauge if I let it go to an idle.

I am trying to determine if there is a galley plug left out somewhere, and that is even what the builder is thinking, but since it has been a couple years now, it is really difficult to go back on them to try and get some resolution.

What my most curious question is, is whether or not there is a double plug in the rear lifter galley as I have read described numerous times on blocks where the distributor is in the rear of the block. My research seems to make me think that maybe there was two styles, a front and rear distributor, and mine happens to be a front mount.

Some other items I have noticed is that when it is running from cold startup, it does not appear to be oiling the rockers well, not much oil is making its way through the rocker shafts. But when using the priming tool and having the D/S rocker shaft removed, oil is definitely traveling to the rocker shaft oil port on the head, but it must just not be able to build enough pressure to push through the shaft.

While using the priming tool, oil is making its way all the way to the rear lifters, but I would expect to see more oil coming out around the lifters, it is a minimal amount.

I am wondering whether I open the timing chain cover next and look at the front oil galley plugs. The drawback to this is once I do that I can no longer manually run the oil pump to see if I can detect the change or abnormality in oil flow. My other option was to pull the engine and go in from the back, if it has the double galley plugs and see if maybe the internal one is missing, but I have not been able to find anything showing that with the distrubutor in the front, that it would still have 2 galley plugs stacked on top of each other in the back of the block.

If anyone could offer any guidance or advice. it would be much appreciated.

Thanks in advance,

Sean