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12-20-2022, 10:56 PM | #1 |
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Ring and Pinion 3.78, 3.54 or 3.25
Anyone running a 3.54 or a 3.25 ring and pinion over the stock 3.78? If so what are your thoughts?
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12-20-2022, 11:57 PM | #2 |
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Re: Ring and Pinion 3.78, 3.54 or 3.25
A friend of mine installed a 354 and had to take his overdrive out it was just too much.
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12-21-2022, 12:19 AM | #3 |
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Re: Ring and Pinion 3.78, 3.54 or 3.25
....
Last edited by Benson; 12-21-2022 at 12:00 PM. |
12-21-2022, 12:32 AM | #4 |
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Re: Ring and Pinion 3.78, 3.54 or 3.25
3.78 with overdrive, 3.54 with a high compression head and touring cam no overdrive.
3.25 same as 3.54 but on flat ground no hills. My 2 cents |
12-21-2022, 06:11 AM | #5 |
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Re: Ring and Pinion 3.78, 3.54 or 3.25
The Mitchell 26% OD takes the 3.78 down to 2.8. With a 3.54 its 2.62.
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12-21-2022, 06:14 AM | #6 |
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Re: Ring and Pinion 3.78, 3.54 or 3.25
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12-21-2022, 07:16 AM | #7 |
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Re: Ring and Pinion 3.78, 3.54 or 3.25
When I got my roadster the ring gear was bad. Replaced it with 3.54 set. 9000 miles later I am still satisfied with the performance. Lots of local trips, 20,30 miles. Some over 100. Good performance and 17-18 mpg. This is a 35-45 mph car. Bill
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12-21-2022, 07:51 AM | #8 |
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Re: Ring and Pinion 3.78, 3.54 or 3.25
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12-21-2022, 10:39 AM | #9 |
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Re: Ring and Pinion 3.78, 3.54 or 3.25
3.78 times .26=.983. 3.78-.983=2.787, or 2.8. .26 is the same as 26%.
Same calculation for other ratios. |
12-21-2022, 10:42 AM | #10 |
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Re: Ring and Pinion 3.78, 3.54 or 3.25
3.78-.983=2.797. even closer to 2.8
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12-21-2022, 10:46 AM | #11 |
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Re: Ring and Pinion 3.78, 3.54 or 3.25
I agree with others above that the 3.25 rear end ratio with a stock engine will be too much. Your car will die on hills and headwinds.
Been there, done that with a stock 35 Ford, and put a 3.78 back in the car. A Model A will be similar. |
12-21-2022, 11:07 AM | #12 |
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Re: Ring and Pinion 3.78, 3.54 or 3.25
I run a 3.54 in a '47 Tudor. Flathead powered, all stock engine. It's perfect for cruising. I know it's not Model A but I like the 3.54 in the V8's.
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12-21-2022, 11:28 AM | #13 |
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Re: Ring and Pinion 3.78, 3.54 or 3.25
Hey Ron, I've run 3:54 in our 31 S/W Town Sedan with a B motor for 45 years, it's run great but will be putting in a Mitchell and probably go back to 3:78 gears.
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12-21-2022, 12:00 PM | #14 |
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Re: Ring and Pinion 3.78, 3.54 or 3.25
Update: 12-30-22
Engine is and was Fresh rebuild Model B with 5.2 Police Head (Head with the LARGE B) I removed 3.54 and put 3.78s in. Installed Mitchell with 15% 1st / 15% 2nd. With 26% Mitchell over drive. Still too high in OD LOW range for driving on "real back road" mountain roads. Plan is to put the 4.11 rear-end back in and use the 26% Mitchell to drive above 50 MPH. Last edited by Benson; 12-30-2022 at 12:11 PM. |
12-21-2022, 12:05 PM | #15 |
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Re: Ring and Pinion 3.78, 3.54 or 3.25
As Benson and others have stated above, it depends on many other things. I ran a 3.27
:1 R&P in my speedster for awhile, it is a light car and I live in mostly flat country. It was fine on the highway but not so good from the stop light. I switched to a quick-change so I can run the highway or on hill climbs, as-needed. My widebed has 4.11's and a 26% Colombia, I love it! |
12-21-2022, 12:50 PM | #16 |
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Re: Ring and Pinion 3.78, 3.54 or 3.25
deleted
Last edited by Benson; 12-24-2022 at 08:29 AM. Reason: Spelling and grammer |
12-21-2022, 02:37 PM | #17 |
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Re: Ring and Pinion 3.78, 3.54 or 3.25
Newly rebuilt upgraded (HC head, Model B intake manifold, right cam) and a "lighter" vehicle (i.e. pickups, roadster, coupe, possibly Tudor) I would go with the 3.27.
Reasonable engine in good shape, not upgraded, light or medium vehicle loaded with family and used regularly nearing 55mph do the 3.54. Worn engine not upgraded, little need to go above 55 do the 3.78. I have the 3.54 in my 29CC pickup. On the trip moving the vehicle to New Hampshire, I had my Dad follow behind me in the family wagon - a "just in case." We traveled Route 110 from Central Massachusetts all the way up into SE NH, traveling through every small town along way. The rationale being to stay off of a major highway namely Route 495 in case there was an issue with 55mph. (The then state speed limit, although most went faster.) I did not have the proper gears to make the speedometer "correct." So my actual speed appearing to me was a conjecture. On our successful arrival in New Hampshire, Dad says to me "Yunno, at times you were going faster than 65mph on those back roads - maybe you should hold it down being the brakes are as they are (i.e. not real good) on your truck?" So maybe the highway would have been a safer option? Joe K
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12-21-2022, 03:39 PM | #18 |
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Re: Ring and Pinion 3.78, 3.54 or 3.25
The correct math is 3.78 / 1.26 = 3.00. No subtraction with gear ratios.
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12-21-2022, 04:12 PM | #19 |
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Re: Ring and Pinion 3.78, 3.54 or 3.25
When my 3:78 went bad - upgraded to 3:54. PicUp is entirely stock - I have no idea if gas milage improved -- don't care either. An excellent purchase for South Florida
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12-21-2022, 04:46 PM | #20 |
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Re: Ring and Pinion 3.78, 3.54 or 3.25
When my rear went bad in my coupe, I went to the 3.54 and I've never looked back! I love it! It climbs hills much better. It gets better mileage! The engine runs slower. I live in this rock pile in Northern Bucks , Pa. It does better on the hills than before. I am running a"Head", ratio unknown,"B' manifold and Carb (estimate 45 to 50 HP) and that's it! Much improved!
Terry |
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