I would go with the fluidyne. I checked the specs for the factory replacement one and the fluidyne one on summit. The fluidyne looks to be a lot better but if there is a cost issue involved then you might want to go with a junkyard rad. The fluidynes are in the neighborhood of $450ish. The modulars are good engines and dont generally have any overheating problems unless you really neglect them but they are extremely susceptible to heat soak which robs power like crazy. I would maybe go with the fluidyne and a 190* thermostat or a 160* thermostat if you have it tuned.