I'm replacing the water pump on the '81 and questions began to arise. Do I want an aluminum pump instead. Some pump higher volumes of water, but are these really a practical upgrade ? Besides being more expensive, the manufacturers don't seem to want to warranty them past 30 days, kinda unnerving. I'd love to hear the voice of experience on the matter.

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Jimmy B.
Just can't wait to get on the road again.

 
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I've used the HD cast iron models for years with no failures.

 If the GENERAL put them on it, they will work. CAST is best.

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Most 'luminuminum pumps do have improved impellers that will flow more volume of coolant, which is not a bad thing. Is it worth the extra $$$? Not in my opinion, unless yer fightin a heat issue to start with. I'd stick with the plain jane pump, meself.....just get ya a can of AlumaBlast while yer at the parts house and paint it...no-one will ever know.

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Joel Adams
C3VR Lifetime Member #56    
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"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

Thanks guys, I love this place. With too many cars, I've ordered a mess of parts on line, and when you make a mistake or change your mind (and I've done plenty of both) it's just not worth it sometimes to exchange items. I'll take this order in to town to my local Napa.

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Jimmy B.
Just can't wait to get on the road again.

 
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I posted several months ago about a leaking weep hole problem I had with a parts store iron pump.  Took it back to the parts store (about 5 years later) and they replaced it for free.   

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Given equal design, the only difference between a cast iron water pump and an aluminum one is less weight and possibly better heat transfer.  The coolant doesn't care what material it's passing through.

Stewart Stage One cast iron pump will move more water and outlast stock or rebuilt pumps. The last one I installed was still working well after 10 years when the car was sold.
If concerned about original looks, the pump housing is an OEM unit machined inside to flow better.

http://www.summitracing.com/parts/EMP-13103/

I've been using the Steward Stage 1 high-flow for several years with no problems. This was one of many things done to fight my high heat problem.

here's my story, bought a polished alum. WP on e-bay for 78.00 delivered,alum. impeller, 30% more volumn and a lifetime warr., for my rat rod, I'am feeling good about the deal so I go's to put the WP pulley on and its rubin on the heater hose and by pass boss I'am using stock chev pullies, what the &&^^%$# and I lift the hood on the vette cause I run Edel. on it, I noticed that the boss's have a flat spot in those area's to clear the pulleys, so's I figure I'll file the areas a bit to get some clearence I filed about 1/16 off and still not enough, so now with the spacer kits, and a new pulley I could have bought an Edel. , after filing on the pump there goes my warr. you really have eyeball the photos of the products you buy on line or made oversea's