Jon,
There was a discussion(thread) on this very subject. Some seem to think you need a high volume pump. Others think that if you move the water too fast, it negates the ability to pick up the heat properly. Still others think a low volume pump will suffice. The number kicked around most was the 55 GPM pumps. There are some up to 110, and some as low as 19. I myself have a Moroso pump and it is around 19 if memory serves. Most manufacturers make the pumps(and output) specific to engine size.
Then there is the argument of whether to run a thermostat, a large washer, or a thermostat with a bleed hole drilled in it. Then whether to run a bypass thermostat even with a remote unit. Do a search for Electric water pump here and you will find 10 pages of post . Only some of them will be of value because the way the search engine works. You will find many arguments for types, sizes, and flow rates.
Most think mine is too small. It is the correct pump according to Moroso for the 351W. But in fairness, mine is bored and stroked. It should be on the road soon and we will find out if it is adequate. Those here on the forum have heard this from me at least 40 times. Things keep getting in the way, and I will leave it at that. I did have my engine running and without a thermostat and the temps never got above 160-180 while sitting on jack stands. Maybe driving it will make a difference. We will see.
Bill