I come up with the following on NAPA's website using a 1972 GMC 3500 w/350 engine (they didn't list the 5500, but should be the same if the engine is the same.)

NRO 4N4795 or RAY 2464795 or RAY 2464803 or NRO 4N1091 or RAY 2441601


Kevin
1951 Chevy 3100 work truck
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Photos
1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car)
Busting rust since the mid-60's
If you're smart enough to take it apart, you darn well better be smart enough to put it back together.