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07-22-2023, 12:31 AM | #1 |
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Automatic tranny in a Model A Ford
Looking for information about using a Ford C-4 or C-6 transmission to a Model A block. I know of one locally but the man who made it has since passed away.
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07-22-2023, 12:47 AM | #2 |
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Re: Automatic tranny in a Model A Ford
Try Bendtsen’s Speed Gems Transmission Adapters. I think they use GM transmissions tho. Or check with Flat-O. I used their adaptor to install a C-4 behind my 318" Y-Block in my '55 Ranchwagon.
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07-22-2023, 01:13 PM | #3 |
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Re: Automatic tranny in a Model A Ford
C-4 and C-6 are better suited for high horsepower V8 engines. I think they used a C-3 in the pinto that would rob less horsepower from the 4-banger. I have a C-6 in my '57 Ford, but it's with a big-block.
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07-22-2023, 01:20 PM | #4 |
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Re: Automatic tranny in a Model A Ford
C-6 is way overkill for a Model A
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07-22-2023, 02:25 PM | #5 |
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Re: Automatic tranny in a Model A Ford
There is a Model A repair specialist here in the DFW area that put an early GM Power Glide in a Model A for a client. From what I've heard it worked out well, but I don't know the details firsthand.
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07-23-2023, 01:17 AM | #6 |
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Re: Automatic tranny in a Model A Ford
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07-23-2023, 11:35 AM | #7 | |
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Re: Automatic tranny in a Model A Ford
Quote:
A A4LD would be a nice trans to concider, basically a C-3 with O/D. Bendtsen's has a kit https://transmissionadapters.com/pag...r~mk_ford-a4ld |
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07-23-2023, 04:09 PM | #8 |
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Re: Automatic tranny in a Model A Ford
Any automatic trans. hooked to a 40 HP stock model A is going to be a significant loss of power. The engine can be souped up to increase HP but then there is always the weakest link in the frame or drivetrain that people experience. I don't know what change in mileage would occur. The advantage of having an automatic and ease of driving might outweigh the power loss for many people. Here's a list of power loss on popular transmissions published by a Car Craft article.
Powerglide - 18 hp TH-350 - 36 hp TH-400 - 44 hp Ford C-6 - 55-60 hp Ford C-4 - 28 hp Ford FMX - 25 hp Chrysler A904 - 25 hp Chrysler 727 - 45 hp
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07-23-2023, 05:41 PM | #9 |
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Re: Automatic tranny in a Model A Ford
The chart of drag is a nice set of data. Remember, the converter of an automatic has slippage up to cruising speeds. Which means that at 25MPH you are losing some efficency, as the converter has not yet achieved theoretical speed to get it to 1:1 yet. We also need to remember, that the converter should always be sized so that the "stall" is less than the RPM at highway speed. Otherwise the thing will never hit 1:1.
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07-24-2023, 04:31 AM | #10 | |
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Re: Automatic tranny in a Model A Ford
Quote:
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07-24-2023, 04:37 AM | #11 |
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Re: Automatic tranny in a Model A Ford
Their kit that can use a Chevy TH200c trans mentions the lockup torque convertor will get you an extra 300 rpm.
Instructions: https://cdn.shopify.com/s/files/1/00...f?v=1592251539 Some of the other modifications that need to be addressed are: parking brake, manual brake linkage, torque tube rearend, crossmember, automatic shift linkage, cooler lines, etc. The transmission that I think works best with this setup is the 200/c transmission. It has the smallest overall case size and is very light. (about the same as the C4). It isn’t an overdrive transmission, but it has a lockup torque converter which can be good for about 300 rpm at highway speeds. It also has much better gear ratios than the 350th or the 400th, and is very reliable when built correctly. It would be wise to take into consideration how much horsepower your engine has before using an automatic trans. By nature, the front pump of the automatic transmission uses some available horsepower to run. If you are using a stock engine, you’ll have very little horsepower left to drive the car. Removing the heavy stock flywheel also means less available torque at low RPM’s. The stock flywheel delivered quite a bit of torque via inertia (rotational force). This kit works best with a modified engine. In the end if you want an automatic a Pinto 2.0 or 2.3 with trans may be the best bet since the engine has enough HP to overcome the loss with an auto. Last edited by ModelA29; 07-24-2023 at 04:43 AM. |
07-24-2023, 06:45 AM | #12 | |
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Re: Automatic tranny in a Model A Ford
Quote:
Steve Becker at Bert's had a complete Model-A 904 transmission conversion set-up for sale at one time. He likely has sold it but he may be able to get another one. |
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07-24-2023, 09:19 AM | #13 |
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Re: Automatic tranny in a Model A Ford
IMHO, converting to an automatic takes so much away from the Model A driving experience that it no longer is a Model A. I understand that physical limitations come into play and that one would want to continue in the hobby even after one is no longer able to shift a manual transmission, but why ruin an original Model A? I believe Shay replicas were available with auto trannies. Again IMHO, the Shay replica would be just as much a real Model A as a Model A where the tranny was swapped out for an automatic.
There's one on ebay now: https://www.ebay.com/itm/16620044669...Bk9SR8ij8oOxYg |
07-25-2023, 09:11 AM | #14 | |
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Re: Automatic tranny in a Model A Ford
Quote:
Put on a HC head to help offset the horsepower drag of the automatic.
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07-25-2023, 09:42 PM | #15 |
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Re: Automatic tranny in a Model A Ford
Why?
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07-26-2023, 07:42 AM | #16 |
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Re: Automatic tranny in a Model A Ford
While I can' speak for the OP, IMHO the "why" for an automatic transmission can be 'justified' for many reasons in today's society. "Why" do some feel the need to convert to 12 volt electrical systems? "Why" do some feel the need to convert from Babbitt to Insert Bearings?? "Why" do we feel the need for automatic advance distributors??? "Why" the need to change to different F100 steering boxes, electronic ignitions, carburetors, 16" wheels, or (you fill in the blank)????
What some may feel is a valid excuse may not be as valid for someone else. Think about it, how in the world did a handicapped person ever manage to drive a Model-A back in the 1930s?? |
07-26-2023, 08:53 AM | #17 |
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Re: Automatic tranny in a Model A Ford
when i was rebuilding a ZF transmission for a Peugeot 404 wagon it seemed like a good starting point for a automatic for the A, it’s short, has a removable bell housing and has torque tube drive
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07-26-2023, 09:08 AM | #18 |
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Re: Automatic tranny in a Model A Ford
Peugeot trans, p.16 & 18 https://www.peugeot404na.com/_files/...18713f8369.pdf
Doesn't call for cornhead grease in the U-Joint! It must have been cheaper to have the closed driveshaft, it sure increased the dread unsprung weight. |
07-26-2023, 01:19 PM | #19 |
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Re: Automatic tranny in a Model A Ford
There's probably many good Auto transmission options that will work in a model A. The GM powerglide looks like a good option because of the low drag to operate it. I would not recommend it for an A though because it's a two speed trans. 1st gear can really wind out before shifting into high. That's why drag racers like it. The GM TH200-4R is about the size as a powerglide and has a very low drag but same bolt pattern on the bellhousing as the powerglide. 4 speeds means keeping the A engine in the low rpms and overdrive is .67:1, so it's like having a Mitchell for highway cruising.
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07-27-2023, 10:37 AM | #20 |
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Re: Automatic tranny in a Model A Ford
If it means I can continue to drive my Model "A" while in my late 80s, I would gladly have an automatic transmission installed.
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