FlowKooler water pump
 

I am installing a FlowKooler cast iron water pump on my 68 GTO 400.

I know that with a standard water pump the distance between the pump veins and the backing plate must be adjusted for better cooling but what about the FlowKooler brand that already has it's own separate plate covering the veins?
Does the FlowKooler design not need any more adjustment?:confused2

I would have to say that it depends on if the flow cooler impeller is an improvement over the stock one.

Does it look different then your stock one?

If not then I would measure your gap between the plate and impeller and adjust / tap and bend it as you would for a stock pump.

Tighten up the clearance as much as possible between divider plate and impeller, without deforming anything. I tried a 8 bolt FK pump, wasn't really impressed vs a $49 iron impeller reman from NAPA. Your mileage may vary.

If you will be using the 8 bolt pump, I would say just make sure your pump doesn't rub with the plate, and call it good. The FK impeller design has its own plate design to make the impeller more efficient: water goes in at the center, gets flung by the vanes to the outside where it is directed to the 2 block channels. A factory pump might need a little plate massage for efficiency, but I don't think the FK needs massaging.

FlowKooler water pump
 

Old photos--I guess FlowKooler has "improved" on this.

Aluminum pump housing, looks like OEM iron impeller--cut down to smaller diameter, and with a shield spot-welded to the impeller.

NOT thrilled with the spot-welding job.

I would still tighten up the clearance since even with the added plate the coolant can still do strange things in the void. Best thing I can say about spending the additional money on a Flowkooler is that it doesn't do any harm.

I agree, spot welding steel to cast iron is iffy.
The factory could have done this but went with just a stamped plate / baffle to eliminate one potential failure point..

I also don’t like the reduction in impeller hight.

I had the old style FK with the spot welding, was NOT impressed. Drug on the divider plates, didn't cool as well. Best thing I ever did on a Pontiac was go 11 bolt pump. Engineers do stuff for reasons.

Maybe this new design is better? Still not as good as 11 bolt at low speeds.

I did contact FlowKooler and they say to tighten up the clearances.

Flowkooler
 

When you make this adjustment on a factory pump is the idea only to bring the edge of the hole in the divider plate close to the impeller vanes? Or is it necessary to bend the whole surface surrounding the hole in the divider plate closer to the vanes?