| deluxe40 | -- 06-26-2010 @ 10:10 AM |
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Has anyone installed a Speedway 3.25 gear set in a '40 Ford? The current 3.78 just isn't tall enough for the L.A. freeways. I was thinking of a Mitch*ll overdrive in my Sedan Delivery until I measured the floor pan and discovered there is only 12 inches of clearance between the rear flange on the torque tube and the step down in the floor (for the fuel tank). Any advice would be appreciated.
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| supereal | -- 06-26-2010 @ 10:35 AM |
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I have a Ryan OD in my '47, and although the clearance to the floor pan is closer than 12 inches, it has never been a problem. My unit is a 3 to 1 (33%) bolted to a 3-78 axle. The OD is fine on the highway, above 45 mph, but lugs down considerably at lower speeds, such as in-town traffic. I can run on the hiway at the usual 60-75 mph, but don't do it often, given the rather primitive braking and handling of my '47. I do use it when cruising on the two lanes, unless it is in very hilly country. I believe you would find that with a 3-25, you will have an objectionable loss of power off the hiway. The Mitch*ll is well recommended, and I would go that way. 12 inches of clearance is more than enough.
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| danliveshere | -- 06-26-2010 @ 3:13 PM |
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Do you think a 35 with fresh rebuild would handle a 3:78 with 30% Mitch*ll overdrive? I've had a 35 roadster for 24 years but it ran a merc and 3:78, never actually driven a 85 horse 21 stud motor to know the best ratio?
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| 37RAGTOPMAN | -- 06-26-2010 @ 4:20 PM |
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I have a 354-1 from the V8 SHOP in BALLSTON SPA NY, and am happy the way it works, seems to get better milage and can cruise a 60 or better, but like staying in the speed limit, KEEP ON TRUCKIN 37RAGTOPMAN
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| supereal | -- 06-27-2010 @ 10:36 AM |
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You will find some difference between the 21 and 24 stud engines. My convertible is a heavy car, and has plenty of low end power in traffic with the 3-78, but can't get out of its own way if I forget to lock out the OD. With the 85, I'd be cautious about lowering the rear ratio. The difference between a 3-78 and a 3-54 is only about seven percent, not much for the cost and trouble. Most OD units provide 25-30 percent. The idea is to keep the engine in the best power band, around 2,000-2,500 rpm. You hit that around 50 with the 3-78. With a 30% OD, you will running about 65 at that rpm.
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| Pauls39 | -- 06-27-2010 @ 1:42 PM |
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We just got back from Charlotte with a 40 pickup running a Mitch*ll OD. It ran well even in the mountains of Virginia and West Virginia. The OD slowed the motor enough to allow it to run cool and we had the option of going back to the 3.78 if we needed the power. The OD replaced the torque tube with no clearance problems. The installation is simple. It took longer to decide the route for the shifter cable than it did to install the rest of the unit.
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| deluxe40 | -- 06-28-2010 @ 10:45 AM |
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I was all set to order a Mitch*ll Overdrive for my '41 Ford Sedan Delivery (on a '40 Tudor frame). Then I noticed that there is only 12 inches between the rear flange of the torque tube and the point at which the floor pan drops down to accommodate the fuel tank (originally behind the seat). As shown in the photo below, there is 9" of clearance between the torque tube and the rear floor for only the first 12 inches (from the rear). Then the floor drops down 5 inches leaving only 4 inches of clearance for the next 3 inches. At 15 inches the top of the torque tube is level with the flat part of the floor. Looking at the photo in the V8 Times I don't believe there would be enough room to install the overdrive unit. I just sent a note to Mitch*ll to verify, but I'll be surprised if the unit will fit without modifying the floor. My second choice was the 3.25 gear set. I just bought a '46 Sedan Coupe that the previous owner said has a 3.25. It drives just fine (for me). So much so that I'm a little suspicious that the gear might be a 3.54 rather than a 3.25. i counted the teeth on the ring gear and got 39. That would indicate 3.54 (with a stock 11 tooth pinion.). However, it might also indicate 3.25, if the pinion has 12 teeth. Does anyone know how many teeth are on the ring and pinion of the 3.25 gear set from Specialty? Also, are there any special issues with installing the gear sets from Specialty? If I don't get this settled soon I'll have trouble keeping up with the trucks in the slow lane on my way to St. George.
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| supereal | -- 06-28-2010 @ 11:26 AM |
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The clearance isn't a problem. The only objection I had to my OD was the lever control. We made a bracket at the OD end, and installed a truck PTO cable with the knob just befow the dash on the left side. I'm not familiar with the Getz gear set, but we have put together a number of the old style rear ends. It is a big job, requiring considerable assembly and disassembly of the axle to get the lash and mesh correct. Installing the pinion and bearing assembly is also tricky. Simply swapping torque tubes is considerably less work.
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| Pauls39 | -- 06-28-2010 @ 7:15 PM |
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The Mitch*ll OD is available with a Cable shifter or a solid rod your choice when ordering. The 3.25 sounds a bit steep, but that would depend on your motor's HP. I like the versatility of the OD.
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| Texas40 | -- 06-29-2010 @ 7:04 AM |
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I have a speedway 3.25 gear, it has a 12 tooth pinion which gives it a 3.25 ratio with the 39 ring. I have not found the power loss everyone else seems to believe. I live in Texas so its probably not for West Virginia driving but LA or Texas flat roads its fine. I find its perfect. I rarely going up a very steep grade so you might have to use second occasionally but its been so long ago that I experienced that I can't even remember it. Performance and cooling advantages at highway speed make it perfect for me.
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| deluxe40 | -- 06-29-2010 @ 7:35 PM |
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Thanks to all for the feedback. Mitch*ll Manufacturing got right back with a note telling me that their Model 1000 is 10 inches square and extends 3 inches both up and down from the drive shaft centerline. They install it 6 1/2 inches from the banjo. So it looks like I need 16 1/2 inches where I only see 15 at the most. They also said that the floor in a '40 business (opera) coupe does need to be modified, but the floor in a regular coupe does not. I'm thinking Ford used the business coupe floor pan on the delivery to make room for the gas tank. Next step is to make a cardboard mockup to see what might need to change. Thanks also to Texas40 for verifying that the 3.25 has 39/12 teeth. That means I am still not positive what I have. Maybe I can put white dots on the ring gear and the crank pulley and then turn the engine until the ring gear goes around once and see if the engine has turned 3 1/4 vs. 3 1/2 times. With the inevitable slop in the drive line it will likely be hard to tell. p.s. There was a complete Columbia at the L.A. Roadsters' swap meet last week - $4250.
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| supereal | -- 06-30-2010 @ 9:16 AM |
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Look for a set of numbers stamped into the bottom "web" of the rear end banjo. It may be hard to spot without scrubbing the area. If you find it, divide one number into the other. For instance, if you find 34-9, you have a 3-78 ratio. 37-9 shows a 4-11. 3-54 shows up occasionally. That would show 39-11. Some internals have been replaced over the years, but mostly the stamped numbers will be true.
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| deluxe40 | -- 06-30-2010 @ 4:17 PM |
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Bottom of the banjo has "9 34" so the gear set has been changed because the ring gear has 39 teeth. My wife was reluctant to crawl under the car to watch the ring gear turn so I decided to jack up one rear wheel and have her watch the other wheel as I turned the engine over while watching a chalk mark on the crank pulley. Each revolution of the engine turned the rear wheel about 2/3 of a revolution. Must be something about spider gears I don't understand. For my next attempt I put the car on the ground in high gear and, with the remote starter switch (and the ignition keys in my pocket), I cranked the engine until the rear wheels had made one revolution. At that point the crank pulley had made 3 revolutions plus about 20 degrees. An exact 3 revolutions +15 degrees would have indicated 3.25 while an exact 3 revolutions +32.4 degrees would suggest a 3.54. Given that 20 is closer to 15 than it is to 32.4, I'll say the car has a 3.25 gear. I then went for a nice long ride to replenish the charge I burned off of the battery and make sure I really like the gearing, even in town (I do).
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| supereal | -- 07-01-2010 @ 11:41 AM |
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To count the teeth of the ring gear, both rear wheels have to be off the ground so the spiders don't interfere. I'm not sure how you counted the teeth on the ring gear if you didn't have the axle apart. That is the only way you can actually see the pinion, too. 34 divided by 9 in 3:78. Ford didn't supply a 3:25 rear. If you actually have a ring gear with 39 teeth, it is very likely you have a 3:54 ratio (39-11).
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| deluxe40 | -- 07-01-2010 @ 7:47 PM |
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To count the teeth on the ring gear I jacked up the back of the car so the oil ran toward the front, pulled the oil filler plug, put a small drop of white paint on one ring gear tooth (after wiping off the oil), waited overnight until the paint dried and then turned a rear wheel while counting teeth until the white dot came up again. I have done this on four cars lately and it works great. I even scr*ped off the drop of white paint when I was finished. A high intensity flashlight is helpful. I agree that a 3.54 is possible because both the 3.54 and the 3.75 use a 39 tooth ring and I can't see the pinion. However, the previous owner's statement that the car has a 3.25 plus my experiment that showed the engine turns over only a little more than 3 1/4 turns for one revolution of the wheels make me lean toward 3.25. I'm still hoping the previous owner has a receipt that will document the 3.25.
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| Texas40 | -- 07-02-2010 @ 6:29 AM |
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To Supereal: Speedway does offer a 3.25 gear (I have installed one and also have another new one in the box)> Not genie Ford but with the 12 tooth pinion and 39 tooth ring it does deliver 3.25. I was impressed with performance in a 21 stud engine car I installed it in so I bought one for myself.
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| supereal | -- 07-02-2010 @ 9:53 AM |
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I agree, but Ford never installed such a set, so if the count is correct. it had to be a replacement set. Unless you live in a dead level part of the country, a 3:25 rear would be a problem. If the new owner was told that it had a 3:25, and his count is correct, it may be true. Not all sellers are truthful, of course, but embellish the list of equipment, as many have found out too late.
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