I'm running a 515ci BBC. On a long 5000 rpm run my oil pressure starts to slowly fall off. 3000 rpm it's at about 55psi. after about a minute at 5000 it starts down.

Stats: 10 qrt pan, Valvoline Racing 20w-50, mechanical gauge, Fram HP4 filter, Oil temp 195-205 (at filter before cooler).

If I stay on the throttle it'll drop to 30 psi.

I just changed the Oil. Found no metal in the filter.

Where do I start?

In addition:

It's always fallin off a little I just never noticed it to be this drastic.

I wonder if the oil can't return to the pan fast enough and your starting to "run low" and sucking some air?

Saw that on the dyno a little while ago. 10 quart pan with 10 quarts actually needed 11.5 quarts when turning 6000 rpm.

Probably need a bigger oil cooler.

not if he has stable 205 temp... should actually be a little higher...

hand for me to believe its not draining down because at 205 it flows like water and ive never seen a v-8 able to trap 6 or 7 quarts of oil in suspension...

this sounds more like he is beating the oil into froth. but thats just a guess...

my 502's will sit at 4900 as long as i care to do it it at 220 deg oil and 50 psi ... all box stock.

ive read threads here where people have described the overfilling causing this and made a sensible argument. 205 should be no big deal if the clearences are normal.

I'm wondering how he's taking the temp at the filter????

Also, if thats as high of oil temp as he's getting, he would probably be seeing some condensation. It may not be giving an accurate temp where its being taken.

I agree, he may be whipping the oil also. It also may not have enough oil. A 10 qt pan is going need at least 11 quarts with the lines, cooler and filter.

First thing I would try is another brand of oil, you never know..years ago at the race tracks nobody would run valvoline...I have never either...thats where I would start...Rob

the filter housing has a sending unit port machined in it

is this a stock engine? maybe something to do with cooling of the oil...