i had a lose of oil presure and had to change my oil pump. now engine starts with great oil preasure and the it drops way down. i did find a bunch of metal in the oil pan. do you think that this is the main bearings??? i dont think that it is the rod bearing because there is no noise coming from the engine.

 

Most cold engines start with great old pressure although after reaching operating temperature the pressure will drop quickly if you have worn main or rod bearings using thicker oil or installing a high performance oil pump will help but bad bearing are bad bearings and should you not replace them you are likely to get stranded on the side of the road with a hole in the engine block.

The general rule is 10 PSI for every 1000 rpm is the low end of proper engine oil pressure.

 

With a bunch of metal in the pan you are looking at an engine rebuild. If it isn't taken care of now you will be stranded as stated above.