I'm in the process of reviving my 1966 gt350 that came factory with an automatic transmission. When my dad bought this car in the early 1980's it wasn't running and missing some original parts. It's been in storage ever since. I have been reading that after car #800 they came with the 4100 series carb. my car is #366. What would be the correct carb? The last time this car was on the road and running was 1978. It's time to get it road worthy. My next question did the automatic cars come with the tri-Y headers? I have the motor apart and found it has a spun rod bearing and one of the cam bearings were installed incorrectly blocking the oil passage. It has a standard bore. Any info would be greatly appreciated.
Thanks
Robert
According to the registry all automatic cars were built with the 460 CFM Autolite carb with manual choke.
Quote from: trotrof1 on August 06, 2026, 09:31:37 PMAccording to the registry all automatic cars were built with the 460 CFM Autolite carb with manual choke.
Quote from: Rbuddy98 on August 06, 2026, 08:37:02 PMI'm in the process of reviving my 1966 gt350 that came factory with an automatic transmission. When my dad bought this car in the early 1980's it wasn't running and missing some original parts. It's been in storage ever since. I have been reading that after car #800 they came with the 4100 series carb. my car is #366. What would be the correct carb? The last time this car was on the road and running was 1978. It's time to get it road worthy. My next question did the automatic cars come with the tri-Y headers? I have the motor apart and found it has a spun rod bearing and one of the cam bearings were installed incorrectly blocking the oil passage. It has a standard bore. Any info would be greatly appreciated.
Thanks
Robert
The correct carb for your early #366 (non carryover) would be the S2MS marked 3259-1 Holley carb. Later cars typically used the 4100 carb through the end of 66 production. It would also have Tri Y headers like every other 66 GT350.
Just to offer a bit more help for you and others reading this thread.
(https://www.concoursmustang.com/forum/gallery/23/6-060826220225-235022039.jpeg)
(https://www.concoursmustang.com/forum/gallery/23/6-060826220204-235011098.jpeg)
Great info Bob. What do you think a good date range for that carb would be for a late Nov - mid Dec 65 build date? Preempting the next probable owner question.
The SAI part number will be S2MS-9510-A. The Holley LIST number will be 3259 or 3259-1. The early carb will not have the SAI part number, but just the Holley LIST number. The carb below came on an early November San Jose built car with a October 24 engine assembly date. Getting one with an applicable date code will cost a little more. Best of luck.
Do you have the San Jose estimated scheduled build date? I would gestimate mid September 1965. Looks like SAI shipped 6S366 on December 28, 1965. The date code for your carb will start with the "5" for the year and for month likely "7" for July, "8" for August, "9" for September. But as info "O" for October,"A" for November and "B" for December. The last character is the week in that corresponding month.
Assuming the original block is still with the car, the engine assembly date should get you closer to narrowing in on a carb date.
Cory
Thanks Guys for the info. I found a carb in my hoard of parts that has stamping of S2MS-9510-A List 3259-1 721
I think from what everyone is saying that would be for a 67 Shelby gt350. will this be ok to run my 66. Would the jetting be the same for a 66 and 67. Also where do I go to buy the correct Tri-Y headers.
Thanks
Robert
Hi Robert, your 721 date code carb should work the same as the original carb. The best tri-y's might be Scott Fuller. Very spendy. Shelby Parts and Restoration may still have them.
Cory
I would guess it was closer to mid Oct possibly into Nov 65, looking at other cars with similar Shelby VINs, but we'll not know or even be close without more data points to compare to. Of course the carbs were built in batches so some cars would have receive "recently" made carbs or much older stock depending on other factors and the luck of the draw. Sounds like your not really focused on dates and you have something that will work. As far as jets in the carb there is no way of knowing if the ones in yours have been changed so time to pull it down and check to see what the little number on the side tell you and go from there.
Quote from: J_Speegle on Today at 02:25:04 AMI would guess it was closer to mid Oct possibly into Nov 65, looking at other cars with similar Shelby VINs
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+1
Correctly dated parts isn't everyone's priority but if I were to happen to come across a closely dated carb I wouldn't ignore it.
Quote from: trotrof1 on Today at 10:01:33 AMCorrectly dated parts isn't everyone's priority but if I were to happen to come across a closely dated carb I wouldn't ignore it.
Yes I would like to get it running and driving with period correct parts. Date codes aren't as important but if I can find the right date codes for a reasonable I would buy it.
Keep your options open. Someone might trade you for your 67 unit. Originality tends to yield a higher valuation. Something to consider while moving forward.
I have a 501 dated carb if you'd like it. That is first week of October 1965 and, in my humble opinion, is about as perfect a date for your application as possible.
Kind regards,
Vern
vestes85"at"gmail . com
I would pull the trigger on Vernons carb. Think of it as an investment with compounding interest.