You need to know if your pump was a long or short pump in order for for belt pullies to line up and have your fan the proper distance in the shroud. Mine is the TA 1537 BHP short pump. If your looking for a stock replacement short pump I have a brand new one. I ended up going with the hi flow heavy duty pump. You can get the flowkooler pump in long or short and in polished or raw aluminum.
No, they are probably just measuring differently. An easy way to ID long or short is to look at the pump shaft extension beyond the fan clutch mounting surface on the water pump. The long pump is 1", the short pump is 1/2".
I’m thinking i may go with this 6 blade fan. I’m thinking it may be a little more efficient than the original 7 blades. https://www.summitracing.com/parts/der-17118/
When it arrives dry fit it on, put your pulley and belt on and see if it lines up correctly. If not you may be able to shim behind the pulley with washers to bring it out an 1/8".
That hub is pressed onto the water pump shaft. Basically all you have to do is pull it 1/8th. off for things to line up. OR you can use the washers as mentioned.
If the pulley is to far in by that 1/8 inch .. Washers will do the trick.. But what works better is take a spare pulley and cut the center out. Takes time but worth the effort.
Skip the washers and pulley mutilation. As mentioned the hub is pressed onto the shaft. A 2 or 3 jaw puller will effortlessly pull it into position. Test fit it before you install it for good. If you go to far the hub will need pressed back.
You shouldn't need to be pressing anything. I've replaced water pumps many times in my Buicks and never had a problem with pulley alignment. If the manufacturer doesn't care to make the pump right in the first place, it would go right back to them. JMO.
Our water pump is a cast aluminum housing that we machine in house and I personally assemble. We use bearings, seals and flange that are made in America. The impeller is cast aluminum that we machine and have hard anodize coated to prevent corrosion. Our water pump casting has much larger water passages than a common pump and the casting is much thicker. Our impeller is a positive displacement type so it prevents cavitation, builds more pressure, and flows much more than typical "finned" impeller designs (stock and flow kooler) that rely on the clearance between the fins and the timing cover to seal and build pressure. More pressure in the cooling system prevents steam pockets from forming and reduces cooling system temperature. One of the most important changes on our 455 pump is the sealing surface between the inlet cavity on the pump and the impeller which doesn't exist on any other pump (the surface between the impeller and the triangular inlet cavity in the picture below, up and left of the part number). Our pump casting seals against the timing cover so that the inlet and outlet cavities are separated from each other. A stock type pump (and flow kooler) is "open", so pressure on the outlet side can bleed back into the inlet (high to low pressure differential). Very inefficient design that we corrected. The flow kooler is simply a Made in China stock replacement type pump that they disassemble and then put back together with a different impeller. It's a slight upgrade compared to a stock pump but nothing compared to our pump. I wouldn't use one simply from the premise of how it's assembled. They press the bearing out of the pump, and then back in. When you do this, you're reducing the amount of press on the bearing which can cause it to move later on. I actually have a 350 one here right now where that exact thing happened; the bearing was working its way into the pump. The impeller was chewing into timing cover and then wore out the bearing from that all happening. I believe flow kooler wouldn't warranty the pump so the customer upgraded to one of our pumps.
Agreed. I messed with mine because of an aftermarket balancer that was thicker.. ive since put a stock balancer back on.