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11-16-2021, 04:58 PM | #1 |
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3.27 Gear without an Overdrive
I would like to hear from people who are running a 3.27 rear end without an overdrive. Would you get a 3.27 if you had to do it again?
I have a fresh engine that will be getting a HC head and I would like to build this one without an OD. |
11-16-2021, 05:22 PM | #2 |
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Re: 3.27 Gear without an Overdrive
My coupe with 3.78 gears and 6:1 head does pretty good on a long grade in high, but I don’t think it would do so well with 3.27s. Getting up to speed from a stop would be even more leisurely, also.
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11-16-2021, 05:34 PM | #3 |
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Re: 3.27 Gear without an Overdrive
What body style Model A? A Heavier car like a Town Sedan or a lighter car like a Roadster? It does make a difference. Is it the Phaeton in your Avatar?
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Ruth "Sometimes you really DO need to read the whole thread" Last edited by Ruth; 11-16-2021 at 07:52 PM. Reason: Verbage. |
11-16-2021, 06:24 PM | #4 |
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Re: 3.27 Gear without an Overdrive
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11-16-2021, 06:41 PM | #5 |
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Re: 3.27 Gear without an Overdrive
I have a 30 Coupe with a 3.27 rear. My car has a B zenith Carb (the only difference from an A Zenith carb is the presence of a power jet), a B camshaft, modern upper distributor plate, a Snyder's 5.5 head, and a V8 clutch set-up. No overdrive. The car has excellent acceleration and hill pulling power. I love it. Would never think of any other rear end ratio. I can start out in 2nd, but don't do so to reduce clutch plate wear. However, I still turn a lot of RPM's (don't really know how many) at 50mph and am uncomfortable at 55 mph. I am going to put a Mitchell OD in it, and have been waiting 4 months on a waiting list to get one. Car should be really sweet then with a 26% reduction in rpm's engine will be doing 45 mph and car will be doing 55-60 mph. I have no fears that the engine can't handle the OD with the 3.27 differential.
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11-16-2021, 06:53 PM | #6 | |
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Re: 3.27 Gear without an Overdrive
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11-16-2021, 10:35 PM | #7 |
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Re: 3.27 Gear without an Overdrive
I run a 3.27 gear in my BVille car, right about 165 mph at the 2 mile mark....
John
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11-16-2021, 10:49 PM | #8 |
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Re: 3.27 Gear without an Overdrive
its a good thing there aren't many hills.
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11-17-2021, 12:23 AM | #9 |
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Re: 3.27 Gear without an Overdrive
I took my 29 out today for ride in Mitchel high and that was a bit to much being a 26% overdrive or a 3.00 to one ratio. the 3.27 would give the same effect as 15.5% full time overdrive when compared to the standard 3.78. With a high compression head and a strong engine that is doable. Sure she will be a little slow off the line but very happy at 40 to 50 mph.
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11-17-2021, 06:31 AM | #10 |
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Re: 3.27 Gear without an Overdrive
Model A Ron, I would advise against 3.27 in North Carolina unless you stay in the flats. It also depends on how you drive your car. Do you spend more time going on back roads or the interstate? Do you drive it into town or on long road trips? Ford put the 4.11 gears in cars that were shipped to mountain areas. I still think an overdrive is a better solution.
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11-17-2021, 09:14 AM | #11 |
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Re: 3.27 Gear without an Overdrive
I didn't think the 3.27 was available any more, so took a look as Snyder's, they now offer a 3.25.
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11-17-2021, 09:42 AM | #12 |
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Re: 3.27 Gear without an Overdrive
I would not recommend 3.27s to anyone with a Victoria in a hilly area. My Victoria with a healthy stock motor and 3.78s has a tough time with some of the bigger hills around here. A fellow club member experiences the same issue with his Victoria and has installed a Mitchell in one of them. I have a Mitchell on order and can’t wait for it to come in.
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11-17-2021, 09:47 AM | #13 |
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Re: 3.27 Gear without an Overdrive
This A powered hot rod weighs 1700 pounds and pulled 60HP at the rear wheels on a dyno. I tried a 3:27 and found it wanting, even with a '39 transmission and lightened flywheel. I live at 6700' and there are plenty of hills around here. Went back to 3:54 and pleased with the performance. The '29 CCPU in my avatar has a B engine with a CRAGAR head and a T-5 transmission that is the answer from my perspective.
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11-17-2021, 09:54 AM | #14 | |
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Re: 3.27 Gear without an Overdrive
Quote:
The Mitchel OD at 26% with 3.78 gears is wonderful......I have one in my 29 Phaeton and love it. Top end in overdrive is well over 60 but you could drive all day long at 55 to 60 without issue. That said I do not want to go much over 50 with most of my driving. The car will do it but you need to think about the limitations of a car designed for use 90 years back. That said the 3.27 is the equivalent to a 15.5% full time overdrive with 3.78 gears. Starting off in Mitchel high with the equivalent of 3.00 to one gearing is to much and too slow to get up to speed. The 3.27 should be a slow start but doable and happy between 35 and 50 in my opinion. Last edited by Model A Ron; 11-17-2021 at 10:01 AM. |
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11-17-2021, 10:19 AM | #15 | |
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Re: 3.27 Gear without an Overdrive
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11-17-2021, 11:14 AM | #16 | |
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Re: 3.27 Gear without an Overdrive
Quote:
This may be a trivial observation. Typically, percent change is calculated from the starting value. The difference of 0.51 between the two ratios would be divided by 3.78; yielding a 13.5% change. What really matters is the way your car performs. I am curious if there is a change when accelerating from a stop. Faster or slower? With enough torque a light car maybe faster. Having a 3.78 with OD is an expensive way to have it both ways. Last edited by ThosD; 11-17-2021 at 01:25 PM. |
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11-17-2021, 02:02 PM | #17 | |
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Re: 3.27 Gear without an Overdrive
Quote:
FWIW, I actually DO have multiple firsthand experiences running a 3.27 ratio in many different bodystyles and terrains, ...and yes I have one in my own vehicle. Going further, I actually have a 3.25 ratio in a couple of my Model-Ts, and one with a 3.0 ratio and all of my cars have many miles on them from touring all over this country. What I always find sad (-not just here but in other forums & social media formats too) is there will be ones that give their opinion on what won't work well or why it wont work well however when truth is known, in reality they have never actually had any firsthand experience with the advice they are giving to someone else. It's like the person asking the question must decide the correct answer to his question first by needing to determine whether the advice he is given is actually factual or just fiction. There was a time in my life when I remember it wasn't that way. |
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11-17-2021, 02:37 PM | #18 |
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Re: 3.27 Gear without an Overdrive
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Last edited by Hitman; 11-18-2021 at 02:29 PM. Reason: ... |
11-17-2021, 02:44 PM | #19 |
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Re: 3.27 Gear without an Overdrive
My only experience with ratio changes was when I was a kid and didn't know anything and installed a 4.11 rear axle. I didn't even go around the block before I removed it for a 3.78. It was like 3rd gear was 2nd. I have thought of a 3.54 but the difference I experienced back then keeps me from changing things. My car cruises at 50 easy enough as it is.
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11-17-2021, 03:41 PM | #20 |
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Re: 3.27 Gear without an Overdrive
Brent,
My experience with 3.54 with a Fresh B engine with unknown reground cam by Mike Reichter is low end torque is lacking and as such pulling hills or mountain roads is not what I remember from 1962 to 1975 (40,000 miles) with a worn out Model A engine with a worn A camshaft. I have no idea what cam Mike was using in 1989 (except that it was a regrind) and he since died. Do the 3.25 cars that you mention have reground camshafts or Stipe IB330 or IB340 cams? I wonder if reground cams raise torque curve too high to work with the lower RPMs of a 3.54 / 3.25? I removed the 3.54 7 years ago and used a 3.78 which is in car now ... it works much better than 3.54. This Coupe is run from 6000 to 11,000 feet. Thank you Last edited by Benson; 11-17-2021 at 03:49 PM. |
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