I don't know what the radiator with the side brackets goes to. Maybe the folks at
https://vccachat.org/ can answer that one.
One thing to keep in mind with the old honey-comb cores: they might flow freely, but might not transfer heat well. This was the case with Lurch's radiator. I was limited to driving under 25 mph before he would start to overheat.
The new radiator core does a great job at helping Lurch keep his cool.

Now I can cruise between 30 and 35 without any worries.
Ever onward, Dean