Oil Pump For Stock 440

[streetmachine]

Hello. Just to revisit the topic I'm just wondering what would be a good replacement for the factory pump on pretty much stock '75 440 street engine with an automatic? The engine came out of an RV from what I can tell. I've seen conflicting information on high volume vs a high pressure pump. The car is pretty much a cruiser and doesn't see much hard driving. Maybe a full throttle run up to 75 mph on rare occasion and that's about it really. Just wondering what would be recommended in this case? Thank you in advance.

 

[69 Sleeper Bee]

Standard volume pump is what you need if it is a stock motor.
I personally recommend Melling

 

[streetmachine]

Thank you. Yes, it is pretty much a stock engine right down to the cast iron intake and Thermoquad on it. Is Melling still a good brand?

 

[Beekeeper]

Thank you. Yes, it is pretty much a stock engine right down to the cast iron intake and Thermoquad on it. Is Melling still a good brand?

Melling is an excellent pump

 

[69 Sleeper Bee]

Melling M-63

 

[gkent]

"high volume" and "high pressure" are actually one and the same pump. If you increase the volume though the same opening then what you have is high pressure. Same as running a pressure washer ... you only get increased pressure by increasing the volume of water. So the only pump choices you have are "high volume/high pressure" or "stock".

 

[OKDart]

Last time I checked, they offer the high volume pumps with a standard pressure spring (60 PSI) or a high pressure spring (80 PSI). If your engine is a fresh rebuild, a standard volume/standard pressure pump is all you need. If your engine has some miles on it, I'd get a high volume/standard pressure. As your engine wears, that space is taken up by oil. You should be OK without upgrading to a hardened intermediate shaft tip with that setup, but it's recommended.

 

[493 Mike]

I recommend that you disassemble, inspect (deburr if needed), and lube every new pump. They were put together by humans.
Mike

 

[66Satellite47]

The difference between "high pressure" and standard is the relief spring in the pump. High volume relates to the rotor size or depth.
EDIT: for a stock style motor, a stock BB oil pump is just fine. Melling pumps are good quality

 

[69Bee]

Sorry, you must have failed physics in high school. Pressure and volume are "Inversely Proportional".. That means, when the volume increases (larger diameter hole), pressure decreases. And in the reverse, when the hole size is made smaller, volume decreases and pressure increases.

 

[zyzzyx]

In a Melling pump, the standard rotor length is 1.0"
On the high volume pump, they are 1.2".
Moves more oil per rev.

 

[Cranky]

Hello. Just to revisit the topic I'm just wondering what would be a good replacement for the factory pump on pretty much stock '75 440 street engine with an automatic? The engine came out of an RV from what I can tell. I've seen conflicting information on high volume vs a high pressure pump. The car is pretty much a cruiser and doesn't see much hard driving. Maybe a full throttle run up to 75 mph on rare occasion and that's about it really. Just wondering what would be recommended in this case? Thank you in advance.

I recommend that you disassemble, inspect (deburr if needed), and lube every new pump. The were put together by humans.
Mike

I agree and one more....it's a very good idea to check rotor end clearance to make sure it has at least .002" clearance. Found one once that locked up because a very tiny piece of trash got into the pump and the rotor end clearance on this engine only had .001". This can be checked with 'Plasitgage' pretty easily. Ended up having to rebuild this already brand new rebuilt engine again.....and no, I'm not one that did it the first time. The owner cheaped out and let the inmates of the county jail do it where he worked as a jailer. Perfect example of new parts not being a slap it on and go deal or letting someone that does that work on your car.

 

[66Satellite47]

Sorry, you must have failed physics in high school. Pressure and volume are "Inversely Proportional".. That means, when the volume increases (larger diameter hole), pressure decreases. And in the reverse, when the hole size is made smaller, volume decreases and pressure increases.

Sorry, you must have failed physics in high school. Pressure and volume are "Inversely Proportional".. That means, when the volume increases (larger diameter hole), pressure decreases. And in the reverse, when the hole size is made smaller, volume decreases and pressure increases.

No didn't fail physics in high school or in engineering school, or in 35 years as an engineer that learned to be be a specialist in pump applications and design. Your statement does not consider all the factors in fluid flow.

 

[69 Sleeper Bee]

Here are all 3 oil pumps a Melling M-63 , M-63HP , and the High Volume pump off my 1970 383 HP motor.
From what I understand the only difference in the M-63 & M-63 HP is the spring in the HP is stiffer creating more pressure and the HP has a tag on it stating such.
The High volume pump is a taller housing to accommodate the taller impeller to pump more oil. I did read somewhere that you should not run the HV pump at W.O.T. for more than 30 seconds at a time or you could suck the oil pan dry so maybe others here can debunk / verify that as I am not sure.

 

[zyzzyx]

The High volume pump will theoretically empty the stock pan because the Mopar Engines manual
says that you need a quart of oil per 1000 RPM. When the oil starts to "Hang out" up in the valve
areas, the sump runs dry. So, if you're gonna run a big pump you better have enough oil! If you
don't need it, don't buy it.

 

[69 Sleeper Bee]

The High volume pump will theoretically empty the stock pan because the Mopar Engines manual
says that you need a quart of oil per 1000 RPM. When the oil starts to "Hang out" up in the valve
areas, the sump runs dry. So, if you're gonna run a big pump you better have enough oil! If you
don't need it, don't buy it.

My 383 HP came with a 6 quart pan but my machinist recommended going with a standard pump for what I am building it for which is street / mild strip.

 

[451Mopar]

The Deeper HV pump needs longer bolts if you decide to go that way.
On a stock engine, either should work unless the bearing clearance is so large the standard volume pump won't create good pressure.
If it is a stock engine, with the silent timing chain, the oil pump pickup screen may be partly blocked with the nylon timing chain teeth.

 

[streetmachine]

Thank you all. I'll be honest and say I don't know the mileage of the engine and there is unknowns about it in which I will have more questions in the future about other engine related things. The engine was already in the car when it was purchased an extended time ago and definitely not a fresh rebuild. I will definitely have to check out (inspect) the pump when I get it and definitely make sure it is clean as well and also verify the clearance mentioned in this thread.

 

[OKDart]

Thank you all. I'll be honest and say I don't know the mileage of the engine and there is unknowns about it in which I will have more questions in the future about other engine related things. The engine was already in the car when it was purchased an extended time ago and definitely not a fresh rebuild. I will definitely have to check out (inspect) the pump when I get it and definitely make sure it is clean as well and also verify the clearance mentioned in this thread.

There are 2 odd sized o-rings inside the pump, plus the gasket for the relief spring. If it's an old pump they will be brittle, make sure you have new ones to replace them. Maybe someone here has a source for those? I've only seen them in a rebuild kit with rotor, etc for $$$.

https://www.summitracing.com/parts/mel-k-63

Also, there's a step by step process in your cars service manual on how to inspect the pump.

FYI, as far as the high volume pump sucking the stock (4 qt) pan dry, the only time that has happened to me (noticed gauge flux) was when I was a quart low and at WOT for longer than 10 seconds.

 

[Old Sparky]

Here are all 3 oil pumps a Melling M-63 , M-63HP , and the High Volume pump off my 1970 383 HP motor.
From what I understand the only difference in the M-63 & M-63 HP is the spring in the HP is stiffer creating more pressure and the HP has a tag on it stating such.
The High volume pump is a taller housing to accommodate the taller impeller to pump more oil. I did read somewhere that you should not run the HV pump at W.O.T. for more than 30 seconds at a time or you could suck the oil pan dry so maybe others here can debunk / verify that as I am not sure.
View attachment 1194847
View attachment 1194853

Yes you can suck the pan dry with a HV pump...it needs a larger pan and a windage tray can't hurt either.