1966 L36 Fuel Pump AC 6440366

[Peter M.]

Page 114 of the 5th addition 66 TIMJG calls out the correct pump as part # 6440366 - yet the picture (M-35) on the same page showing an example shows IH40366! I have an original pump that has part#40366 that matches the description on page 114 of the casting and other attributes - except does not have the 64 in front of 40366. I'm confused! Is 40366 a correct late 65 / early 66 L36 fuel pump?

[Larry M.]

Re: 1966 L36 Fuel Pump AC 6440366

Peter:

For fuel pump identification/stamping not all the part number digits are used. 40366 is fine.

Now be advised that the letters associated with the fuel pump numbers are actually date codes. I do not think our judging has progressed to the point that most judges know how to evaluate them. But this has been discussed in this forum before, and the information is in the archives. David L. is one source of this information. You might search under "fuel pump date codes" or something similar to find these threads.

Larry

EDIT: Here is one link to get you started: https://www.forums.ncrs.org/showthre...ump+date+codes

[Peter M.]

Re: 1966 L36 Fuel Pump AC 6440366

Thank you Larry - very helpful and appreciated.

Peter:

For fuel pump identification/stamping not all the part number digits are used. 40366 is fine.

Now be advised that the letters associated with the fuel pump numbers are actually date codes. I do not think our judging has progressed to the point that most judges know how to evaluate them. But this has been discussed in this forum before, and the information is in the archives. David L. is one source of this information. You might search under "fuel pump date codes" or something similar to find these threads.

Larry

EDIT: Here is one link to get you started: https://www.forums.ncrs.org/showthre...ump+date+codes

[David L.]

Re: 1966 L36 Fuel Pump AC 6440366

IMO the "IH40366" pump would be dated Sept. 1968.
Dave

[Peter M.]

Re: 1966 L36 Fuel Pump AC 6440366

Thanks David - the IH I mentioned was from the picture in the 5th addition NCRS TIJMG - My pump has the 40366 but no letters

[David L.]

Re: 1966 L36 Fuel Pump AC 6440366

Thanks David - the IH I mentioned was from the picture in the 5th addition NCRS TIJMG - My pump has the 40366 but no letters

I would say your 40366 pump is original assuming it has the "AC" casting.
Dave

[Joe L.]

Re: 1966 L36 Fuel Pump AC 6440366

I would say your 40366 pump is original assuming it has the "AC" casting.
Dave

Dave and Peter------


Well, if it's original, it's a "ticking time bomb" at this point.

AC fuel pumps and other AC parts usually followed a strange practice of using different part numbers for PRODUCTION and SERVICE for the same part. For the 1966 big block fuel pump the PRODUCTION part number was GM #6440366. The SERVICE part number for the same fuel pump was GM #6416245 which was discontinued without supersession in 1980. However, the AC type number and the number used if you bought the SERVICE pump from an AC dealer was always the last 5 digits of the PRODUCTION part number or, in this case, 40366. That number was found embossed on the pumps whether PRODUCTION or SERVICE pumps. The only reason I've ever come up with for the difference between the PRODUCTION and SERVICE GM part numbers is that the SERVICE pump was supplied with a gasket while the PRODUCTION pump was not.

By the way, I think there was a modest change in the configuration of the 40366 fuel pump during the years of its manufacture but I've forgotten what it was. Possibly something having to do with the configuration of the inlet or outlet fittings.

[Julio G.]

Re: 1966 L36 Fuel Pump AC 6440366

As a side note as I am restoring a 66 L36, does anyone happen to have one of these fuel pumps laying around, new or used that they would be willing to part with?
Thank you,
JJ