Stop in for a cup of coffee

I think this picture shows the height of the arigenal/6 radiator best.
Coffee has done its job, out to the shop on this 66 degree morning with zero chance of rain today.

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You still have the original radiator intact?
Otherwise maybe scale the hieght from the photo and the tank?

Combination square was great for measuring installed distance above the support.
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I know its a major PIA to put the hood back on just to test the clearance.