The late 261 pump is long enough that it will hit the radiator even on a GMC. The best setup is to use an adaptor plate with the 216 style pump to keep the fan up high so it works. Otherwise you can shorten the water pump shaft but often a mechanical fan doesn't work well. I am running a short shaft pump on mine with an electric fan on the front of the radiator. I have about 1.5" of clearance between the water pump and the radiator but a fan mounted to the shaft would hit the bottom radiator hose.

I'm tearing it out to fit a GMC 302 in there this summer and I expect to have to move the radiator for that, though. I'm going back to a mechanical fan.


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