Personally and respectfully, I do not like the current aluminum radiators as they are not rebuildable, like the copper and plastic/aluminum radiators are. When that aluminum core gets gunked-up, time for a new one.
Especially, but a good idea anyway, is to ALSO seriously consider changing the block core plugs and flushing out the coolant passagesin the block when you do so. Gunk will accumulate in the lowest parts of the block, which is toward the rear. Doing the radiator, in an older car, is only HALF of the situation, but one which usually can get the easiest results.
In looking for a radiator shop, seek out the one most of the body shops or HD truck dealers use. Being higher volume than a neighborhood shop, they might also be more cost-conscious in their pricing and have resources to get a new, quality radiator, if needed. Use RockAuto and AutoZone for shopping and pricing purposes, to see what's out there and at what price.
In the 1970s-1990s, I usually would get a new OEM-quality Modine 332 for my cars as I could buy them for just a bit more than a local shop would charge for a re-core. Never had an issue with them, but those options are not there anymore.
CBODY67