Stop in for a cup of coffee

Morning. Worked on the cooling system on my D-100, yesterday. Looks like the radiator is partially plugged. Seems like no one has one available. Local rad shop wants $100 to rod it out and if any tubes open up then more money to repair. Guess I will call Champion and see how much extra they will charge to change the water inlet and outlet on the V-8 radiator so it will work with the slant six.
Pull it out, lay it down with fittings up and pour a couple cans of rad flush in. Add hot water and let it soak. Backflush.
I heard drano works, but never had the nerve to try it.