Topic: Correct Autolite 4100 date code for 65 FB.

[vinny]

First off let me say hello to some of the most knowledgable people around on early model Mustangs. This is my first post so i would be what most call a newbie. Anyway im glad to be here. I have a 1965 Fastback built Oct 14 1964, "A" code 289 with a 4 speed, no A/C,no PB. Im trying to find the correct model Autolite 4100 for this car but i'd also like to know what tag date code would be correct also. Its a dearborn car. Any info would be greatly appreciated.

[J_Speegle]

Based on what I'm seeing on other original cars the date spread (in the sample) is two to four months prior to the projected build date so for an oct 64 car maybe  any date in June - Aug 64

[midlife]

You're looking for C5ZF-C, -E, -J, or -L.  The first two have road draft tubes instead of PCVs.

[vinny]

I just bought a C5ZF-E Autolite 4100 Carb with a tag on it that dates it B 5CB(65 March , 2nd week). But then on the base under the carb plate its dated 9-1-64. What gives with this. Is it possible that the tag is not the right tag for the carb or is the date on the bottom not relevant. Im confused. Thanks

[J_Speegle]

I just bought a C5ZF-E Autolite 4100 Carb with a tag on it that dates it B 5CB(65 March , 2nd week). But then on the base under the carb plate its dated 9-1-64. What gives with this. Is it possible that the tag is not the right tag for the carb or is the date on the bottom not relevant. Im confused. Thanks

Chance that the carb was rebuilt some point in the past the the shop doing it swapped individual parts of the carb for one reason or another. Not unusual in rebulid houses that do a high volume. Lots of owners have lost their original heads, intakes, transmissions..... this way

[vinny]

Thanks for the insight. So should i continue to look for the proper metal tagged carb or does the date on the mounting plate suffice for date correct. I have a feeling there is really no way to ascertain if either date references on the carb are accurate. As you say it could have gotten swapped or substituted by the carb rebuilder. Also am i looking for a 65 date tag or a 64 date tag? The c5zf part number is a 65 part number for a carb installed in late 1964, in my cars case. Im a little confused about the proper date code that should be on the metal tag on the carb. Thanks for all your help in answering these questions. Vinny

[jwc66k]

I just bought a C5ZF-E Autolite 4100 Carb with a tag on it that dates it B 5CB(65 March , 2nd week). But then on the base under the carb plate its dated 9-1-64. What gives with this. Is it possible that the tag is not the right tag for the carb or is the date on the bottom not relevant. Im confused. Thanks

The 9-1-64 date you found may be the date the housing was cast if it was part of the housing. From that raw cast housing, different jets, boosters, venture and adjustment were used to make carbs for different applications. Your car's DSO might also determine whether or not you had a road draft tube. Looking at the 65 Shop Manual, there is no difference in the jets, boosters etc. There is another posting on this forum about when the change over was made between the -C and the -E, and the -J and the -L. I think that determination is still ongoing.
Jim 

[Brian Conway]

     FWIW.  The carb on my San Jose, GT fastback car has the C5ZF C stamped on the base @ the forward, left bolt hole.  The tag is stamped C5ZF C and the date is C5EA.  Delivery of the car was the end of May 65.  Brian

[meltdwn65GT]

You're looking for C5ZF-C, -E, -J, or -L.  The first two have road draft tubes instead of PCVs.

Check your information for accuracy.

The C5ZF-J tagged Autolite (with a C5ZF-C on side of base) has a road draft tube. A C5ZF-C tagged (with C5ZF-C on side of base) uses a PCV.

The C5ZF-E tagged (with C5ZF-E on side of base) uses a PCV. The C5ZF-L tagged according to my records does not use a road draft tube.

I just bought a C5ZF-E Autolite 4100 Carb with a tag on it that dates it B 5CB(65 March , 2nd week). But then on the base under the carb plate its dated 9-1-64. What gives with this. Is it possible that the tag is not the right tag for the carb or is the date on the bottom not relevant. Im confused. Thanks

That is the mold date on the bottom (driver side, rear) and the raised 9-1-64 date is a correct match for your tag date.

The 9-1-64 date you found may be the date the housing was cast if it was part of the housing. From that raw cast housing, different jets, boosters, venture and adjustment were used to make carbs for different applications. Your car's DSO might also determine whether or not you had a road draft tube. Looking at the 65 Shop Manual, there is no difference in the jets, boosters etc. There is another posting on this forum about when the change over was made between the -C and the -E, and the -J and the -L. I think that determination is still ongoing.
Jim

There is no maybe involved it is the mold tooling date.

     FWIW.  The carb on my San Jose, GT fastback car has the C5ZF C stamped on the base @ the forward, left bolt hole.  The tag is stamped C5ZF C and the date is C5EA.  Delivery of the car was the end of May 65.  Brian

Next time you have your carb. removed from the spacer and look on the bottom you should have a raised 9-1-64 date on the driver side rear of yours too.

[meltdwn65GT]

First off let me say hello to some of the most knowledgable people around on early model Mustangs. This is my first post so i would be what most call a newbie. Anyway im glad to be here. I have a 1965 Fastback built Oct 14 1964, "A" code 289 with a 4 speed, no A/C,no PB. Im trying to find the correct model Autolite 4100 for this car but i'd also like to know what tag date code would be correct also. Its a dearborn car. Any info would be greatly appreciated.

Based on the above

-Correct for a road draft tube setup would be a C5ZF-J tag with (C5ZF-C on the side of the base), bottom of the base mold date is usually 7-27-64 (for August - Sept '64 tags). Aug-Sept. '64 dated tags would also for information be a Change Level A. *Check your intake to see if its original and rear for the road draft tube provision. Also the DSO (to determine state (emission laws)) on your data plate.

-Correct for a PCV setup would be a C5ZF-C tag with (C5ZF-C on the side of the base). Same as above, bottom of the base mold date is usually 7-27-64 (for August - Sept '64 tags). Aug-Sept. '64 dated tags would also for information be a Change Level A. *Check your intake to see if its original and rear for the road draft tube provision. Also the DSO (to determine state (emission laws)) on your data plate.

NOTE: A Change level A carb. is generally not going to idle/run as smoothly as the Change Level B carb. you presently have. Additionally the carb. housings with a July mold date are usually physically rougher than the September (9-1-64) housings, esp. at bottom of base!

[midlife]

My source was Mannel's book, and I mis-read the footnotes; my bad.

[livetoride60]

-Correct for a road draft tube setup would be a C5ZF-J tag with (C5ZF-C on the side of the base), bottom of the base mold date is usually 7-27-64 (for August - Sept '64 tags). Aug-Sept. '64 dated tags would also for information be a Change Level A. *Check your intake to see if its original and rear for the road draft tube provision. Also the DSO (to determine state (emission laws)) on your data plate.

If your car came with a road draft tube, it should be valve cover mounted not intake mounted for an Oct 14 1964 build date.  Ford replaced the intake mounted draft tube at the start of the 1965 model year, i.e. Aug '64, with a valve cover mounted design which ran through Mar '65.  So if your intake is original, it shouldn't have the draft tube mount on the back machined either way, and therefore won't help determine draft tube vs PCV.  Your intake should be a C5AE-9425-M with J stamp, or C5OE-9425-A with A stamp if original.

As mentioned, you can check the DSO to help determine PCV vs draft tube.  Also, if you're lucky enough to have an original non-drilled out carb spacer #C4OE-9A589-F or the skirted oil filler cap with the word FRONT on top, either of those would indicate a road draft tube.  Even a drilled out carb spacer doesn't eliminate a road draft tube, as they used those spacers for draft tubes as well.  A rubber cap and clamp was used to cover the hole in those configurations.

There are always exceptions, but this is consistent with Bob's book, my Oct '64 San Jose car, another original Feb '65 road draft tube car I've seen, as well as multiple forum posts. 

Please keep us posted. I'd be interested to learn what you discover.