Single or double?

yeah, sort of. it's all interchangeable but with the change over the waterpump outlet moved along with the timing marks on the timing and the lower radiator outlet. so if you run the wrong combo of parts you either can't see the timing marks or you have to jog the lower radiator hose from one side to the other directly under the fan.

you could take the rad to a shop and have them add a core to make it 3 and move the upper inlet to a "more correct" location. dead center isn't great because of possible interference with the fan and if it's in the "correct-ish" location you can run a stock hose that fits nice and looks good!

depending on the cost of adding a core and moving the pipe, i'd maybe look toward an aluminum aftermarket solution.


time to break the cycle amigo!

parts of a molded hose and some solid tube can make for a much cleaner and solid install. here's a vast selection of them: Coolant Tubes - Free Shipping on Orders Over $109 at Summit

You'll probably have to modify it for fit. Things like slot the mounting holes so it fits lower, and what I did on one is also desolder the mounting brackets and reattach so the core and tanks were as far forward as possible. Didn't need to do all that on the /6 replacment squaretops but did on the v-8 squaretop I had.
[URL]https://www.forabodiesonly.com/mopar/threads/340-radiator.418366/post-1972239819[/URL]

If you run a regular fan, then finding the right spacer to clear should be doable.
I ran the 5 blade 'Mopar Performance' clutch fan (after the flex fan incident) which is why I increased the clearance as much as possible.
It moved the air pretty well and may have been OK stuck in summer traffic if there was a fan shroud. But there wasn't and coolant temps would slowly climb when not moving in hot weather. Didn't happen often but it happened. Never enjoyable, and always less than thrilling running the heater fan in the summer. That's all with no A/C.
When the bubble top went in, I bought the correct fan (used) and clutch (new), and shroud (new).
Are there any negatives to just using an older water pump? The cast iron ones are fairly reasonable in price. Is it just the timing marks that are the issue?