My ’56 7.5 has an aluminum plug installed to replace the bailer impeller. It’s epoxied in and all the unnecessary holes were tapped and then plugs were installed. I can’t remember if I tried running it without the impeller but it was blowing exhaust out of the inlet fitting on the side before the plug was made. Now it pumps cooling water like a fire truck! In the future I might put it back to original as I have some Honda impellers on hand which are supposed to work.
A hard impeller wouldn’t work as the pump housings bore is offset from the driveshaft centreline and needs flexible vanes to function properly. I do like that thought though!
