Having just replaced the radiator in my 56 TR3 using the tech tips I would like to add a few things to the instructions when doing this exercise on a small mouth car. The instructions are right on but the small mouth car needs the radiator with the hand crank hole in order to feed the crank bolt through to remove the fan extension. I would guess that the later TR3 with the fiberboard ducting allows for more movement forward of the radiator which will allow the bolt to be extracted. The hole also makes it much easier to remove/replace the fan bolts as well if you do not bolt the radiator down until you have finished as you need to move the radiator a bit to line up the various bolts. Other than that it is not a major project to replace the radiator without removing the bodywork in front.