94Sleeper

Has anyone dropped an oil pan with a six speed? My 383 is dropping oil pressure above 4000 rpm and I am planning on replacing the current oil pump (Melling M55) with a blue printed OEM Pump with a white hi-pressure spring. I was planning on retaining the stock 5-qt. oil pan.

My machinist told me that he installed a standard volume Melling M55 pump, (A standard volume pump) and he does not understand why I am having this problem. All I know is that my oil pressure is at 70-80 psi until around 4,000 RPM where it starts to fall off. I have read the oil pressure threads but they do not distinguish between an M55 (standard volume) and an M55HV (high volume) pumps.

Last week I tried to remove the pan by jacking the motor off the mounts and found the oil pan does not want to come off with a six speed bolted to the motor. My next approach will be to drop the k-member out while the motor is supported and remove the pan with the motor in the car. This should allow me to drop the pan and access the oil pump.

Has anyone replaced an oil pump this way before?

Josh-'04 GTO

What is your oil pressure at say 5000 RPMs? Does the car drop oil pressure in park at those RPMs or just while driving? I would definately like to hear a little more before I condemn the oil pump. BTW, 70-80 psi is double what you need at 4000 RPMs....

RCF925

You can get the pan off if you loosen the bolts on the K-Member about 3/4" then you will have enough clearance to get it off though you have to move it around until you find the right angle, I pulled mine off that way a few months ago. I also have a Melling HV pump that was blueprinted before I installed it and was tested at 65 psi. I don't see that much on my gauge, most the time it's at 45psi after warming up, But you also have to remember on these LT1's they put the oil pressure sending unit at the top of the back of the manifold which is quite a ways from the oil pump and you probably see 10psi less than you really have. A more accurate place to measure the oil pressure would be down by the oil filter where there is a fitting above it.

94Sleeper

I did a search and found some good information in the advanced section about this very problem. It sounds like the pump is OK but I will either need a better windage try and baffle or a new Canton oil pan. Either way the pan has to come off. Thanks RCF925 for the help on lowering the K member instead of dropping it.

One thing I need to figure out now is whether I will need to install a new pickup on my oil pump if I get the Canton Pan.

xxsaint69x

to remove the pan, u need to jack up the motor of the motor mounts and while pulling the pan off, you need to rotate the crank