MP Oil Pump Question

I have a new MP high volume big block oil pump, part number P4286590, installed on my yet to be run engine. The engine is a 400/470 stroker and I was planning on using a factory 187 notched oil pan as it is going into my Dart. I was just reading an article that said when using a high volume oil pump that a 7 quart pan should.be used. Is this true? If it is, will a standard volume oil pump be sufficient for this engine or will I need to go with a higher capacity oil pan?

I had to correct this. I have a 187 oil pan, not an 893.

I've ran high volume, high pressure oil pumps in all my BB engine builds since the early 1970 with 5 and 6 quart oil pans with no issues running them dry on the street or at the 1/4 mile tracks ever as long as the pan is full when sitting cold
My last pump gas car, 1971 duster with a 517 C.I. 400 block ran 10.30 at 127 MPH in the 1/4 mile with Eddy RPM heads, I moved that motor back right at 1.0 inches to the rear so the stock 1970/71 hemi 440 six pack 6 quart would fit in that car, I let it get down to the add mark before one race at Woodburn, OR 1/4 mile race track, it would start to drop oil pressure a little after I let off past the finish line adding the quart of oil fixed that

I use a thick rotor pump in my race car. Even with 6.5 qts it never loses pressure on accel. But this is 1/4 mile only.
Doug

So here's the deal ... on motors with significantly more clearances on the bearings, etc. you want a high volume pump to keep those bearings lubed. BUT on a motor with more normal bearing clearances that extra volume isn't needed and so it builds pressure and that opens the bypass. The oil going through the bypass picks up extra heat. Also, as pressure increases so does the load on the pump drive shaft, gear, cam and subsequently the motor. So running a HV pump in a motor that doesn't need it not only puts strain on the parts, it also costs HP to run it. I'd go so far as to say that 90% of the motors using a HV pump don't need it. Just my 2 cents.

i'm in the middle. I use a stock pump/pressure relief on my stock engine car. I use an hv pump with a stock pressure relief on my modified engine car. works ok for me.

In the old days everybody wanted more pressure and more volume. Sounds like a good idea, doesn't it? Today's thinking is a little different. Mainly people have found out that you don't need the high pressure. You already have the HV pump so if money matters you can use it. People have been running them for 45 years. But in reality now-a-days (and I think this is really a Super Stock development) people have found out that the high pressure of the old days is unnecessary. So I would put a stock pump on it. If you find out after driving it that you need the HV pump (because of excessive clearances or whatever) you could put it on then. But I'm guessing the stock pump would be fine. But since you have the HV pump, if money matters, run it.

"I've ran high volume, high pressure oil pumps in all my BB engine builds since the early 1970 with 5 and 6 quart oil pans with no issues running them dry on the street or at the 1/4 mile tracks ever as long as the pan is full when sitting cold"

What is the actual volume of an 187 pan? I checked my service manual and it says a 72 400 has a 4 qt. pan plus an extra qt. for the filter.

"So here's the deal ... on motors with significantly more clearances on the bearings, etc. you want a high volume pump to keep those bearings lubed. BUT on a motor with more normal bearing clearances that extra volume isn't needed and so it builds pressure and that opens the bypass. The oil going through the bypass picks up extra heat. Also, as pressure increases so does the load on the pump drive shaft, gear, cam and subsequently the motor. So running a HV pump in a motor that doesn't need it not only puts strain on the parts, it also costs HP to run it. I'd go so far as to say that 90% of the motors using a HV pump don't need it. Just my 2 cents."

I don't know anything about the clearances whether they are normal or not. The guy who was building the motor for me passed away so I can't ask him. I'm just trying to finish up what's left of the assembly so I can try and get the motor running by spring. What would determine whether the clearances were increased or not?

"I use an hv pump with a stock pressure relief on my modified engine car. works ok for me."

I still have the original pump that came on the motor. So if necessary, I could put the relief valve from it into the MP pump?

"But I'm guessing the stock pump would be fine. But since you have the HV pump, if money matters, run it."

The MP pump is already installed. I would like to just leave it if it is OK but if not, I will change it. Just wanted to make sure I wouldn't have any issues with the capacity of the 187 pan with the MP pump.

Ya got the pump - just use it ... ain't gonna do any harm. Without ripping the motor apart you don't have the info to make an educated decision.

i believe the relief valve is the same, but the spring is different.

please correct me if i'm wrong.

The high pressure springs use to be all black, the standard springs, depending on who made the pumps, where not colored or red or silver. I could see the length differences and the tension differences when squeezing them with me fingers
Most of the high pressure and high volume high pressure pumps would bypass at 80 lbs. cold with 10/30 or 5/20 W oil, my motors would have between 20 to 30 lbs. hot(above 170 F oil temps) pressure with 5-20W depending on the idle RPM
I like and use the high volume pumps with the high pressure springs so I can cut them down to get the pressures I want, way better to have to much pressure to start with than not enough
I shoot for 10 lbs. per 1000 RPM hot (above 150 F), 70 lbs. at 7000 RPM

but the valve is the same cab ?

I have to use this to see which spring it is

Stock oil pump spring 11.5 pounds @ 1.75”
Hemi oil pump spring 17.5 pounds @ 1.75” (sometimes called "black spring")

At some point in your build you should fill the pan with oil so you can check that the dipstick is accurate. Once the engine is full of oil then you can spin the pump with a speed wrench and see how much pressure it builds. You'll want to rotate the engine to the two locations that oil the rocker arms. This is just all standard engine building stuff. During this process you should be able to figure out if you have the correct oil pressure spring for your assembly clearances. If you don't then change the spring now before the engine goes into the car. For a street engine the best compromise is usually a soft spring with one or two shims. The black spring is usually too much pressure for stock type clearances.

all relief springs are interchangeable. the problem with the hv pump is the high pressure relief spring. the factory had 3 relief springs during the '60's. the red stock 45psi spring, black 65psi street hemi, and plain 75psi race hemi spring (rare to find). the hv spring is a 75+psi spring and is totally unnecessary unless your building a bottom end bleeder. I don't think the black street hemi spring is made anymore. anyhow, my engine with the hv pump and stock spring runs 55-60psi hot on the road and I don't use heavy oils or excessive bearing clearances. hot idle in gear 38-40psi. I feel very comfortable with these pressures. excessive pressures will eat up the intermediate shaft and bushing. I chose this combo because I wanted a little more low rpm pressure/volume without the downfalls of excessive road use pressures. the nice thing is that all this can be played with by just unscrewing the relief cap and changing springs or shims.