water pump rebuild

[hanko mechanico]

57 Lincoln 368 Need advice on rebuilding water pump. The first kit I got on e-bay had the correct shaft but bearing was closer to pulley hub than original and impeller had a shorter hub so didn't come up to seal as they want in manual. Now the second kit I received from Mark 11 has the bearing and shaft arrangement as the first one ( not like original) but if I use the original impeller will come up to seal when seal is installed correctly. The first kit leaked but not sure why the impeller has to come against the seal as they are both pressed on the shaft. Does the impeller hold the seal in correct position as I know it doesn't seal there, but the service manual insists the impeller comes against the seal with grease between the 2 surfaces. I am able to see the impeller position on seal through a hose port. I know alot of you probably are thinking why not buy a new pump. First I would need a bank loan to buy a new one and don't have much faith in rebuilt. I would like to keep my original pump on my original engine. I have rebuilt water pumps before , although many years ago, without issues. So if anyone has had experience I would welcome any advice as I don't want this second kit to leak.