Aluminum Water Pump Housing

how about the summit aluminum water pump? anyone tried it? alittle cheaper in price than the mopar http://www.summitracing.com/parts/sum-314441 Also was curious, on the Jegs website it says Quote "Mopar Aluminum Water Pumps feature basic high-flow designs. The six-blade water pump is recommended for use with cast iron cylinder heads and drag racing applications. The eight-blade pump is recommended for use with aluminum cylinder heads and circle track applications.". can I still use a 8 blade on a stock 400 engine? I think i can - but just making sure? http://www.jegs.com/i/Mopar+Performance/312/P4286900/10002/-1