56 Dual Quad

[D'S56]

Hi fellas, what is the correct part number for the dual quad fuel pump? Is it a 4346 like 57? Thanks, Daniel

[56 2x4]

Correct

[D'S56]

Originally Posted by 56 2x4

Correct

K ,Thanks!

[emccomas]

I think it depends on when the 56 was built. Early 56 2x4 cars used a 4262 pump. Later 56 and 57 2x4 cars used a 4346 pump.

In Corvettes, this change roughly corresponded with a change from a 5/16 to a 3/8 fuel line (around May of 56). I don't know if the same change occurred in passenger cars.

[56 2x4]

The early design 2X4 was not available on the passenger cars. Corvettes continued to be delivered with the early design well after the passenger cars were delivered with the second design due to factory overstock of Corvettes.

[D'S56]

I believe that the 4262 pumps where for the 4bbl power packs for 56. Daniel

[emccomas]

The 1956 passenger car AIM pages for RPO 411 are dated 2-6-56 (sheet 2.01). Numerous revisions occurred throughout the model year.

My April 1, 1956 parts catalog shows:

55-56 ALL, 8 cyl.,
55-56 CORV. 8 cyl.........(flange stamped 4262 or 4150)......5593256

The AIM page that shows the fuel pump (sheet 3.01) shows pump 5594346. This sheet was redrawn on 6-11-56.

Based on this information, my conclusion is that the 4262 pump was used on 2x4 cars approximately between 2-6-56 and 6-11-56.

I am curious about the fuel line on 56 passenger cars. Does anyone know if the fuel line size changed from 5/16 to 3/8 for later 2x4 cars?

[56 2x4]

You present a good argument emccomas. One thing to keep in mind is that there were no computers or e-mail communication, so the preparation, approval and printing of official documentation took longer than we've become accustomed to. Do you have any support from a Technical Services Bulletin? Chevrolet distributed alot of these for the new engine.

[D'S56]

I have an old parts book 1929-1959

3.900 Pump Assembly-Valve Unit-Hose-Elbow-Adapter,Fuel,With Gasket

56-57 All(8cyl.) (exc. dual 4BC,Ser.6)...w/gasket(AC-4460)...5621616 1 8.70

56-57 Pass. w/dual 4BL,
56-57 Corvette ...(type 4346) w/2 gaskets...5593951 1 16.20

Don't know, there were so many changes, hard to nail down. Daniel

[emccomas]

My March 1, 1957 parts book has:

56-57 PASS w/dual 4BC,
56-57 CORV.......type 4346 w/2 gaskets...5593951

The 4346 pump replaced the 4262 pump sometime in mid 1956.

The 4346 pump appeared on Corvettes in mid May of 56. The 4262 pump was used on Corvettes from January through mid May. I would expect the usage on 2x4 passenger cars to be the same.

Are we having fun yet?