[DIYGuy]

I was looking for info on the pros/cons of using an aluminum radiator, and found this thread. Read the entire thread in an evening (I was up 'till 2:15 AM today reading!)

So, today, I checked my rebuilt 'short-shaft' pump - the good news: it has a cast impeller. I got it from a local Kragen some time ago.

The result: the starting clearance measurement was well over .25"! I could put my pinkie in between the plate and the impeller.

This is on a newly rebuilt .030 over 455, which has not yet been installed in the car and driven, so I can't comment on the results except to report back in a few weeks (I hope!) and tell you all how cool it runs.

Oh, yeah, this was a really easy tweak. I followed the method outlined in Jim Hand's performance book appendix. Only thing was that I had to tap the plate down quite a bit to get the clearance I wanted, and it didn't want to go as far as needed, and the clearance varied around the circumference (slightly "wavy"), so I resorted to a bit of body worker's 'heat shrinking' of the metal using an LP torch and a wet rag... once I did that, the last bit of adjustment went very quickly indeed. I'm down to less than .050" clearance, and it looks much better.

[photos added] - first two are 'before', last one is close-up of 'after' clearance.

In closing, I'm so glad I found this thread... thanks all!