"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.