I have a couple minor questions that I think I know the answer to but I would appreciate confirmation.

I recently purchased a stock radiator overflow tank off of a junked 1978 D100 to install on my 1976 D100. My 76 had no overflow tank stock but it does have the original hard fabric/rubber air shroud between the grille and the radiator. The stock overflow tank sits on the top of the grille in front of the radiator in the same space currently occupied by the shroud.

Question 1: do I need to remove the factory air shroud to install the factory radiator overflow?

Question 2: I need to get a radiator cap designed for an overflow tank for the system to work properly, right?

Thanks.

Yes, you need a double-seal cap. See here.

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Too many people who were born on third base actually believe they've hit a triple.

Thanks, Dan! I thought I remembered reading a well written Allpar article about cooling systems and radiator caps.

Much obliged, good sir. That's one of five chapters in that cooling system series I wrote for Allpar.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

I have read through your cooling system series numerous times. It is very informative and helpful. I just couldn't remember where I had seen the discussion of radiator caps in relation to overflow tanks. Now I know where my first stop for cooling system questions is!

Reed, it looks like if your truck has no tank there is a full width that goes across the top like you have now. With the tank two small seals are on the ends only.
Im not sure, but it seems like you should be able to trim the long seal to make room for your new tank.
Then there’s the aftermarket. I bought the fender to frame seals from Dodge Connection. The material and shape of these seals appear to be an exact match for the oem pieces.
http://www.dodgeconnection.com/page/page/2901770.htm
The tank end seals are shown on this list of items for the Dodge pickups.
I hope this is useful.

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1975 Dodge D100 225 c.i., HEI, Parallel 2 bbl Motorcraft 2150, 904 auto, 9.25" 3.55:1

Hey, thanks! I didn't think to look there. I will see if I can find what I need.