This stage of the conversion process is far more complicated than the mechanical side of mating the Cummins engine to the Allison transmission to the Ford transfer case. Our first order of businessand the easiestis improving the engine and transmissions cooling. The 7.3L Ford radiator and transmission cooler are woefully inadequate, as coolant flows through 3/8-inch tubing. The trucks original hardware is replaced with pieces for a 6.0L-powered 04 Super Duty, which has -inch tubing in the transmission cooler, and the radiators surface cooling area is double that of the 7.3L. The components also bolt right into the older truck without any modifications. View Photo Gallery | 24 Photos Photo 4/24 | The stock Ford 7.3L transmission cooler (top) is tiny compared to the unit thats used on the 6.0L Power Stroke engines. The latter provides more than twice the cooling capacity, and it bolts to the same location as the project trucks original cooler. Selecting the right fan is also criticalmore so than the radiator. The fan from a 99-to-02 5.9L Cummins has a special offset toward the radiator that allows the blades to clear the tach sensor thats mounted on the front of the block, as well as bolts holding the reluctor wheel to the crank. Our salvage-yard 01 engine didnt come with the fan, and now we know why: These fans are very hard to find because they are no longer made. After a lot of searching, we were in businessalbeit $500 lighter in the wallet.
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