I have an 89 model 351w that has been recently rebuilt. That has been about six months ago. When it was first rebuilt it held about 80psi at idle. Now it varies. At higher rpm's it will go to about 70 psi, but at a stop and idle it may drop to about 25-30psi. Could the new oil pump be going bad already or could there be another cause? The oil has not been burnt up. I changed it yesterday. After that it idled at around 70psi for a while and then started back doing the same thing all over again.

 

80 is very high for a stock vehicle, I wonder what type of gauge you're using and how trustworthy it is, I'd want to know that it wasn't a gauge problem before I went further. Actually idle pressure of 25-30 and 2000 rpm pressure of 50-60 is excellent.

 

Thanks daerhldgs2. I appreciate it. The guage is a sunpro. the kind Advanced Auto sells.

 

My stock 460 stays about 90psi when cold. It depends on the relief valve. I would say the engine is probably just breaking in. The bearings were probably a bit tight if the oil pressure was at 80psi hot