either one of the three will "work", the radiator i just took off of mine was a three core with a 23 inch core and had a 29 1/2 space between the two mounting holes on the radiator. if you look at the radiator core support it has two set of mounting holes on the drivers side and just one set on the pass side. so the long and short of it is you can use either one as long as the mounting holes aline up with the core support. i would look for a four core 23 inch. just my .02 good luck jerry