The 350 in my Sportwagon has had a problem with low oil pressure at low rpms for some time. With the help of many on this list (thanks!...the orignal post link is below) I changed the oil pump gears, installed a booster plate and adjustable spring relief valve setup from TA...monkeyed around with mylar shims for the oil pump housing ...finally settling on the default gasket with no shims. All of this improved the oil pressure but not enough...it was stll below 10lbs when hot at low rpms. Finally, I filled it up with sae 50 oil (I am in AZ so I can probably run this all year) and that did the trick. I also tweaked the adjustable springs on the relief valve setup some more. Now the oil pressure is always above 10 at low rpms and is very acceptable at high rpms. http://www.v8buick.com/showthread.php?t=37046
