F150 ****** with overdrive

With more than 56,000 views on this thread alone, and 241 replies, do you think Henry missed the boat on not having an overdrive? :D

I've always said the three main things lacking on the Model A are a higher compression head, counterweighted crankshaft, and overdrive.
More leg room would be next on the list.:)
 
One needs to be aware that there are three overdrive ratios available with the F150 transmission. Unaware of that fact, I discovered too late that I had installed the highest ratio of 42% (I think that 35% is recommended for Model A's)
Fortunately, with an improved motor and lightweight body it pulls this ratio effortlessly up hill and down dale.
I haven't checked what diff ratio I have but presumed it to be standard, but as it was out of a speedway midget it may indeed be lower than normal.
To complicate the issue I have a vintage quick change diff with a slightly higher ratio.
All I know is that at 100kph (62mph) it is pulling 1670 rpm.
The installation uses a MAC's bell housing and requires a Mustang turbo clutch.
Keith
 
Duplication of post #8 which has lost it's photos: To answer your question, the transmission you are looking for is out of an 84-87 Ford F150 2WD pickup with an inline 6 or small V8. It has a floor mounted shifter and the shift knob will have "OD" where the normal "4" would be in a normal "H" pattern 4 speed. Secondly, look at the left side of the transmission case. There should be a casting number "260XXXX". Third, on the right side of the transmission there should be a riveted metal tag with the first three letters "RTS" followed by two letters which will identify the OD ratio. See my chart below of the decoding.
 

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Few other items we found, hopefully covered in prior posts:
****** is heavier than stock model A;
Plate can be made to support ****** on cross member with Float a motors;
Some frame spreaders may not clear the F150 ****** when using stock A motor mounts if/when installing engine with ****** already in car;
Brake/clutch shaft may need special bracket to support shaft end and to accommodate stock A pedals;
Speedo may need calibration , etc.
 
Speedo won't need calibration with the F150 overdrive because the speedometer is driven off the drive shaft. A change in rear end ratio would require a calibration change.
 
whitetm said:
What machine work did you have to do to make this work for you?
Click to expand...

No machine required with the kit I purchased. Complete bolt in.

duke36 said:
Few other items we found, hopefully covered in prior posts:
1) ****** is heavier than stock model A;
2) Plate can be made to support ****** on cross member with Float a motors;
3) Some frame spreaders may not clear the F150 ****** when using stock A motor mounts if/when installing engine with ****** already in car;
4) Brake/clutch shaft may need special bracket to support shaft end and to accommodate stock A pedals;
5) Speedo may need calibration , etc.
Click to expand...

1) True
2) Comes with kit
3) With a little creative ingenuity, works ok
4) Comes with kit
5) Speedometer gear is aft of transmission, will give you the same reading in or out of OD. No need to re-calibrate.
 
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harleytoprock said:
Speedo won't need calibration with the F150 overdrive because the speedometer is driven off the drive shaft. A change in rear end ratio would require a calibration change.
Click to expand...

It's interesting that because the gearbox has an electronic take-off for the speedo, I was told that an expensive solution was required.
However a Ford Falcon speedo cable fitted perfectly.
Also, with the 42% overdrive the speedo reads 75mph when the car is doing 62mph (100kph in NZ)
 
wensum said:
It's interesting that because the gearbox has an electronic take-off for the speedo, I was told that an expensive solution was required...
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You must have a different transmission than I have (which is a Tremec RTS), mine does not have an electronic take off for the speedometer.

... Also, with the 42% overdrive the speedo reads 75mph when the car is doing 62mph (100kph in NZ)
Click to expand...

My transmission is 27% overdrive (4th gear). And since the speedometer take off is the original Model A gear, aft of the transmission, it has no bearing on what gear it is in as to how it reads.
 
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I realize this is an ancient thread on the T170FT RTS. No where does anyone talk about shortening the output shaft for the torque tube adapter plate and universal. Are you all buying a kit that has the output shaft splined and cut and then re assembled back into the case? I understand that the torque tube, driveshaft, and radius arms need to be shortened. Any info appreciated on shortening the output shaft or does someone sell an already modified shaft? I have the 27% OD trans. Like to put it in my 30 Tudor.

Thanks, j
 
I bought the complete kit with all the machine work already done. All I had to do was just bolt it in.
 
CarlG said:
I bought the complete kit with all the machine work already done. All I had to do was just bolt it in.
Click to expand...

Did you have to shorten the torque tube and drive shaft?
Rather than have shorten the torque tube and drive shaft, would the open drive shaft kit be an option? Just asking. Speedway motors has them, Part #9191111.
John
 
jayvee34 said:
Did you have to shorten the torque tube and drive shaft?
Rather than have shorten the torque tube and drive shaft, would the open drive shaft kit be an option? Just asking. Speedway motors has them, Part #9191111.
John
Click to expand...

Shortened drive shaft, torque tube, & radius rods all came in the kit. Open drive line was never a consideration.
 
CarlG said:
Shortened drive shaft, torque tube, & radius rods all came in the kit. Open drive line was never a consideration.
Click to expand...

Seeing as how you have had your kit for awhile, what do you think it was cost for the same kit today, and who from?
Thanks,
John
 
I flip flop on doing open drive versus closed drive, Speedway sells rear end adapter for open driveline. Then wouldn't have to do any machining to output shaft but would have to do more mods on radius rods. Prefer to do TT but need more info on modifying the output shaft etc.
 
The length of my OD Transmission with the AA bell housing to the retainer was 18.3125". I figured out how much to shorten the TT by subtracting the shorter original bell and trans combo from the longer OD set up.
 

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