1974 was an odd year because the 2.0 AND the 2.3 were offered. The early (71-73) cars had a 17" radiator and most of the 74 and up cars had a 20" radiator. However, I have seen '74 Pinto's with a 2.0 and a 17" radiator. Ford just used a flat plate to make up the difference.
You state that you have a 2.3 and that should be most common. There are only these aspects that are important:
1. Automatic or manual transmission (you didn't state).
2. Height and width.
3. Size and locations of the hose connectors.
With those aspect you can likely find a new, universal fit radiator for far less than the stated $400 to recore yours. I've found radiators to be one of the more adaptable items on cars. I've swapped a 20" into my original 17" Pinto with a little cradle cutting and welding. I've swapped a bigger 78 Dodge Diplomat radiator into my 73 Valiant simply redrilling a few holes to match. BTW, far better to redrill the car than the radiator because if you ever need to replace it on the road ... . I even baling wired my old 17" Pinto radiator into my 91 Mazda 323 for a month or so until I was approved for the California $1,000 gross polluter buy back program. Like I said, radiator are adaptable.
As LTFM mentioned try a place like Summit and see if they have something that will fit. But I'm thinking that hotrodln was accurate in a 75 radiator would fit just fine.