Hello, I'm just looking for some information and I hope someone can help me.In the thunderbird 390 cubic inch the autolite changed from the (1.12) 600 cfm carb in 1965 to the (1.08) 480 cfm carb in 1966, any reasons why? Also, usually when a carb is downsized the horsepower will also go down yet ford stated that there was a increase in 15 hp for this model year. It all seems strange to me. What I'm wondering is what would happen if you put a 1965 year (1.12) carb on a 1966 model thunderbird. Will it fit? More power ? Anyone have any idea's on this. Thank you Mike

HAY Mr.M,
There are probably some OTHER differences in the engine in addition to the change in CFPM of the carburetor, such as cam, solid vs hydraulic lifters, compression ratio, manual vs automatic transmission, carburetor setup, etc., that would account for the difference in HP.

About the question of the 1.12 physically fitting: Yes, it would physically fit the manifold, linkage, fuel, vacuum supply, though the choke heat supply might be a bit different as there are three different choke heating modes that vary from model to model.

As to whether it would produce more power? Probably, BUT, as you say: The 66 T-Bird came with the 1.08, and if that is true, then the 1.12 WOULDN'T be "proper/correct". If THAT isn't a factor in YOUR situation, then the switch would be just a bolt it on thing. BUT you might want to do some checking on Jet Size, Float Bowl Level settings, and some other variables that would optimize the setup.

You might ALSO check the VIN plate for the fifth position figure (it will be a letter) which would give you the engine specification. Then check that number against the tab that is above the heater on the cowl, to make sure they match. IF they match then the engine setup could be checked to see what the differences between the 65 and the 66 was.

In the final analysis, it all comes down to what you want your setup to accomplish. Is it: More power; Better economy; Proper&Correct; Availability; or maybe some other factor.

Check the VIN and get back to us.

HTH

JC

Heres whats up:

In 1966 to combat the brand new california state emissions, Ford installed special "california emission" carburetors onto their largest FE engines.
For 1966 this included the 390, and the 428 and some 352's.
These were ONLY installed onto big block cars which included the 390/428 Thunderbirds like yours, the 352/390 and 428 Galaxies and the 390 GT Fairlane.

Remember in 1966 no other fords got the large FE engines, The first FE powered mustang was not until 1967.

Yes the US version baseline 390 (or Z coded car) was actually UP 15 more horsepower. This was caused by a boost in compression ratio of 10.0:1 from 1965 to 10.5:1 in 1966.

One of the BIGGEST misconceptions is that the FE "california emission" carbs are the same animal as the small block standard 1.08 venturi carbs. Nothing could be further from the truth. The FE "california emission" carb is specially calibrated to flow at FE levels through the smaller venturi and therefore reduced emissions.
An FE "california emission" 1.08 installed onto a small block will run rich and not run correctly. The jetting, settings and most importantly the venturi boosters and all of the air bleeds and discharge ports of these carbs are set for the FE air volume and the larger vehicles.

When you actually look at this, that 66 Z motor easily gained much more than 15 horsepower with the bump in compression but because of the carb only netted the 15. Interestingly Ford rated the california motor and not the regular motor, people who have had a 49 state Z code have repeatedly reported 325-335 Hp range which would be about right in line with a half of point bump in compression.

Bill White
White Automotive

Of course the 1.12 and the 1.08 are both 4100's so to add to the small block/big block confusion they will completely bolt up, BUT THEY WILL NOT DIRECTLY INTERCHANGE.

Now in your case, its a bit different, you want to replace that "california emission" carb from 1966 with a 1.12. So a couple of ways you can do it:

If you are worried about a number matching just look for a 1966 49 state non-california emission carb, looking for that 6S number on the front foot, of course any 6A would work as well just then it would be from a galaxie and not a thunderbird.
For that matter any 1965 or 64 thunderbird carb would work equally as well. And probably most 65 and 64 galaxies also since these cars used the exact same engine size (390) of roughly the same HP (300-340) and of about the same body weight.

REMEMBER TO NEVER ARBITRARILY START CHANGING SETTING AROUND. EVERY CARB SHOULD BE REBUILT AND BENCH SET FOR THAT PARTICULAR CARBURETOR'S APPPLICATION.

So for example if you install a 1.12 from a 1964 galaxie onto your 1966 thunderbird, when you rebuild that cab, use the specs from the 1964 galaxie to bench set your carb. That will properly set the carb for the factory specifications for that particular model of carburetor and will work for your application.

In your case, if you are not concerned about numbers matching, then ading the 1.12 will take advantage of that bump in compression.

Bill White
White Automotive

Jc & Bill, thanks for responding.I am trying to keep this car mostly correct, but a few simple add ons that can easily be reversed are not a concern.The engine does match the car being a " z" code 390. I am looking for a simple way to increase the power, while still retaining most of the integrity of the car and engine.
My carb is a 1.08 with a (6S A) on the foot.I believe that the car is originally from British Columbia Canada, but I now have it in Kingston Ontario.I gather from your information that this is indeed a 480 cfm carb, though I'm not sure if I understand you completely. Were 1966 1.08's only in California and 1.12's in the other 49 states?
I've seen a few 1.12's in my area at what I think are good prices and was hoping to pick one up. I'm not sure the year they are as I haven't contacted the owners yet.
I'm now in the restoration phase of my thunderbird and I'm trying to come up with some simple options to boost my engine. I thought by keeping the autolite and going to the 1.12 would fit the bill.
Thanks for responding to my questions. It's great to be able to find knowledgeable people to help. Mike.

The "california emissions" carbs were only in 1966, and are very easy to tell.
The part number on the drivers fron foor will always start with a 6 (for 1966) and the next letter will always be an "A" or an "S" or an "O"
The "A" stands for Galaxie (or big car line) The "S" like what you have stands for Thunderbird, and the "O" stands for fairlane.

FORD NEVER PUT A SMALL BLOCK INTO THE THUNDERBIRD, so any "S" code carburetor will be for the FE engine. Everything prior to 1966 for the thunderbird will be a 1.12 venturi 600 CFM. In 1966 they had the two different sizes for the T-bird a 1.08 for california, and the 1.12 for everywhere else.

FORD PUT SMALL BLOCKS INTO THE GALAXIE, BUT NEVER A 4 BARRELL SMALL BLOCK. So any "A" code 4 barrell will be for the FE engine and its the same story, anything before 1966 is all 1.12 venturi and in 1966 the two sizes just like the T-bird.

1966 was the first year for a production FE engine in the fairlane in the GT (I know the T-bolt for 64 but that was a limited production and did not use the autolites). They did make 4 barrell 289's for the fairlane prior to 1966 but in 1966 they did not. So any "O" coded carb with a 66 date would be for the FE engine (only two different carbs) again a 1.12 for everywhere else and a 1.08 for california.

OTher 1.08 carbs with a Z or a D would be for the mustang/falcon line and prior to 1967 never put any FE in them, they were all small blocks.

AGAIN THE MOST IMPORTANT THING TO REMEMBER IS THE SMALL BLOCK 1.08 VENTURI CARB AND THE FE 1.08 CALIFORNIA EMISSION CARB ARE TWO VERY DIFFERENT CARBURETORS.

IF numbers are not a concern I would look for ANY 1963-1966 1.12 carburetor. These will be for galaxies or thunderbirds and are readily easy to find. Any of these carbs should work for you and will bolt right up. I believe it will wake up that 390 and you will like the results.

Those "california emission" carbs really choked those FE engines even though the flow level was intended for the FE engine.

Bill White
White Automotive

Thanks Bill for all your information. I'll see if I can find a 1.12 in good shape to help push this old t-bird a little quicker down the road. Thanks once again, Mike.