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Can anyone help me figure out what year and what this pump was used on?
Pump- on machined boss 17281y
Back plate-7801149 164H D21
Diverter- 7034475
Pulley- 3925522 with a lower S
Pump is dated 172nd day of 1968. Should have a relief valve on the top. The part # you mentioned is not the part # for the valve. The one you are looking for is stamped, not cast, into the valve underneath the cup, but not on it . Should start with 2 something. The pulley is Corvette big block.
Last edited by avalonjohn; Oct 28, 2018 at 08:39 PM.
Here is a '68 small block smog pump and diverter valve. This would have a spacer on the fan then the pulley. You have a big block pulley which would have been mounted directly on the fan without spacer. That pulley and pump would have been used on other GM big blocks besides Corvettes. I am not sure on the diverter valve application, but it was probably used on many big block '68s as well.
smog pump codes??
