What is the correct fan to radiator clearance?

jawbone said
I like your thinking for your issue. Have not heard that approach before but whatever works.

What I did was order a factory spec fan clutch, Hayden 2747, to replace the low profile clutch I have just as you commented on. Your spec sheet is very interesting and has my radiator listed for manual transmission. Cost a bundle. Shroud I have forget where it came from but got it to match radiator. My fan 2863215 not sure what the pitch is. Worked hard not to have a clearance issue. Looks like I worked too hard. New clutch should improve things. I could even shim the radiator closer if need be. Seems like everyone else is going the other way. Did not want to connect and fill just to find out I have a cooling issue. Read many a post on cooling troubles. Thanks for all your input and spec sheet.

That sheet is from the '68 Plymouth Service manual. As you can see my copy is an original but you can get reprints and digital copies. its possible someone built up your radiator using a manual top and a bottom tank for an automatic. Similar idea as when Bob built my car's current radiator using a '68 top tank and a 70 bottom tank.

Well worth the effort you're putting in.
215 is the 18" with 7 2.25" pitch blades