Chifo- go to
http://www.flex-a-lite.com/auto/blackmag.htm for the spec's on the "Black Magic fan, I got mine from Summit.(ships from Reno gets here in a couple of days and the price seems to be the same everywhere) Here's a SPAL link so you can compare your fan specs
http://www.spal-usa.com/html/pgtablel.htm. I did a rough calculation and a 16" fan without a shroud is only pulling from 70% of the radiator. (draw a box, place a circle inside and multiply the corner areas not inside the circle by 4 and you can see it's quite a bit of cooling loss) A shroud by design will draw from the entire core and pull through the fan , probably 95%+ efficent.
Roy- go to
http://www.norcal-saac.org/ and scroll down toward the bottom for info on Historics parking. Contact Lewis Downs.
see ya,
Mike