Fuel pump interchange 1953-55 vs 1956

[Guest imported_UncleBiggy]

From the pics it looks as if they are all the same, but the books all say that 1956 is different from 1953-55. Im thinking that maybe the fuel line locations are the only thing thats different, but I would think a 1956 pump should work on the earlier ones. At one time I put a 1956 water pump(not fuel) on a 1953 and it worked fine except the plumbing was slightly different. Imput???

[critterpainter]

Don't quote me but I believe that the difference is internal. There was a change in the diaphram I believe in mid-55.

bill

[old-tank]

Both of the fuel pumps are backward and forward compatible/interchangeable. The flat top is correct for 53, 54 and early 55 and the dome top is correct for late 55 and 56. On some early models there is interference with the generator adjusting bar and you may need to grind some relief out of the bottom of it.

After comparing the gaskets for the 55 vs 56 water pump, I think that those would not be interchangeable.

Willie

[critterpainter]

If you put a 56 water punp on an earlier Buick, you would have a LARGE puddle of water on the floor, they do NOT iinterchange as the casting is different on one side.

bill

[KAD36]

I've always noticed the 53 to early 55s have the flat top fuel pump with all the bolts around the perimeter of the top. The late 55s to 56 have the dome top with 1 screw in the middle. I've had both installed on my car with no issues.

I'm surprised you got the 56 water pump to work on the earlier engines. Although the mounting to the block should be the same, I think so the 56 pump outlet omits the output line back to the trans cooler - trans cooler on the 56 is in the radiator rather than on the tranny. Somewhere in the garage I have a hose and water flow diagram.