Hey, can anyone explain to me why all these auto part stores have all these powersteering pumps for 1977 k10 with the 350 but how they all have smooth pulley shafts. I just pulled my pump off the truck and the shaft has a threaded end where a nut holds the pulley on and 1 spline on the shaft where the pulley locks into. Will this pulley with the groove work on the smooth shafted ones from the auto parts store or will I have to order one with threads from online.
The old pulley IIRC had a different diameter as well as the keyway etc. You will need either a new pump or a new pulley. id suggest getting a pump for a 1977, which has SAE fittings like your truck has now and a pressed on pulley like most saginaw pumps. nothing wrong with the old kind but they are not the majority for sure.
i have a 1972 engine with that kind i presume, i havent looked at it close but it was pre hei too but has pcv, puts in in that era with the code date saying 72. 1975 gm model vehicles and newer should have the press fit. the 1980 model year saw the threaded connection to the ps gear, so high pressure, go to metric instead of SAE. the fittings can be changed from pump to pump(as does its flow and pressure characteristics) to allow swapping between eras. if you do change pumps, but your reservoir has an incompatible opening for your return line, you can change the reservoir with a cheap seal kit and a way to get it off and press it on. id say boneyard a good pump with a pulley the same size and offset as yours. your engine may have a very flush pulley that fits close to the pump where as some newer ones had double belt accomdation and set the pump in different places and to have more belts moved them in or out.
here is some pumps, 1 of them is Metric the rest are SAE pressed
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the last one is hard to see but passed rad hose is where pump is
