Yes I was curious what impeller people would suggest that I run I have a 1978 Taylor. Day cruiser Ford 460 I am putting a new engine in it should make between 650 and 675 horse not sure on what impeller to run it has an a impeller in it aluminum and the old engine would turn it 5000 RPMs during the day and 5500 RPMs at night from what I have read that is too much horsepower and too many RPMs for that pump what are your thoughts on this please let me know thank you and have a great day


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What pump do you have?


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It's not possible to spin a mixed flow Berkeley clone pump too many RPM.

Actually, the pump will stall the engine where the horsepower curves cross on the dyno sheet and the pump graph.

It's possible, if you have an aluminum impeller and a 304 stainless shaft, and you beat on it, you could break the impeller and/or twist the splines on the shaft with that horsepower.

About one thousand horsepower is the limit for a Berkeley suction housing.  You are already over the limit for aluminum impellers and 304 shafts.  However, it really makes a difference WHERE your engine is making that power AND how you drive it.

A day cruiser is a big heavy boat.  Anything smaller than an A cut is going to suck everywhere but top speed.

I wouldn't recommend going smaller than an A cut.

Consider this, a larger impeller will be easier on fuel consumption during operation.  Are you the type of end user who is out cruising around with the family, or are you out making passes?  Where is the engine going to spend most of it's time, peak horsepower or cruising around?

You can cut a larger impeller down, to increase RPM.  You can (correctly) detail the trailing edges to reduce RPM, however you can only drop a few hundred RPM.  You can't bring a B cut back to an A cut.

Price out stainless impellers.  I wouldn't want to guess wrong or be misled at current prices.  You will spend an easy $3K with the SS impeller, 17-4 shaft, new wear ring, insulator, and thrust bearing minimum.  A BC cut impeller costs exactly the same as a AA cut impeller.

I would try the impeller you have now, to see where your RPM is, then adjust your cut accordingly.  It won't cost you anything except that it is easier to pull the shaft with the engine already out.