V8 60 with mitchell overdrive.

S

strat9973

Junior Member
Looking at installing a Mitchell overdrive in my 37 pickup with a V8 60. It has the stock 4:44 rear end and a newly rebuilt motor. Has anyone done this yet?
 
Mine screams at 50mph. I run out of rear end way before I run out of motor. Just don't know if it can handle a 4th gear. Thought I would ask before I bought.
 
My 1931 Model A pu does fine with the Mitchel od 26% reduction and 3.78 gear ratio. I know your pu is heavier but the Model A has a 4 cylinder engine. I guess it depends how strong the engine is.
 
After the boat racer I bought the stock of nos 60 parts off of told me that in the boat a stock engine would last more than a season at 7000 rpm and less than a season at 7500 I decided that it wouldn't hurt the 39 std with a 60 to wind out the gears a little more and to cruise up the parkway at 70 ---actually the car didn't like running slow, it never finished a parade---but 20min after it died at a parade it was ready to run 100 miles down the parkway at 65-70 ,flat out it could get to near 80 this was a fresh rebuilt engine all rods and pistons were within 1 gram, it ran smooth and if it had mechanical brakes I would still have it.

It probably won't like the overdrive, no torque at low rpm,
 
Thanks for the input. Gives me something to think about. The 60 is certainly a odd ball. Damm thing sounds like a 460 whin I fire it up in the shop, but it has less C.I. Then a Honda Civic. LOl. Go figure.
 
Sounds like you like the current gearing pretty well up to that point. That may mean that the relatively heavy pickup is OK also until that point. The Mitchell is a 27% overdrive making the final ratio 3.24 with a 4.44. Guys that I know that have 60s in Model A coupes find that a three speed in top gear tolerates a standard 3.78 well enough but would not be going to 3.54s because a 60 needs some RPM to make any horsepower at all. Therefore the Mitchell resulting 3.24 is pretty tall final ratio assuming a similar wind resistance to a Model A. I've read a lot of really dumb assed reports about guys boasting silly gearing behind a 60 where a sober evaluation may be that the thing barely runs. My current 60 project but not my first, is a light roadster including a 4.55 rear ratio connected by a Commercial 60 transmission with gearing tailored to getting the thing rolling. I won't run all the numbers because they are not the current question. We're back to the 4.55 in third gear with the 27%. This is clearly not great and more ideal would be less overdrive such as the no longer avalilable Ryan OD at 23%. Remember that we're not dealing with some torque monster engine where you can power your way out of bad gearing choices. To make the 60 work well we need to pay special attention to the numbers and not expect there to be any wiggle room. Getting as close a practical to the tried 3.78 number is where I want to be. In a few words, Good Luck with those Mitchell numbers. Fred A
 
Low powered engines won't pull with to high of gearing.The Columbia is 28 % which works perfect with a 3:78 in the V/8s. I have at least 8 V/8s setup like this and never had any pulling power problem. I was a Ryan OD dealer for a number of years and they recommended a higher ratio for modle "A"s, I believe it was 33%. I questioned them but they said that's what everyone was useing. I put one in and at 45 MPH when I put it in OD it didn't have enough power to go any faster. I put in their lower one which I believe was 26% and it worked fine. In my opinion when you shift from 3rd gear into OD you should feel a gear change very close to the feel you get going from 2nd to 3rd gear with a stock rear. G.M.
 
One interesting thing about the 60...there are published dyno sheets on various Ford engines in the service bulletins, and unlike the other 8's and 4's the 60 power curve is headed UP at the point they cut off the chart. It apparently likes a few more R's than Ford wanted to discuss...
 
For a very short period of time in 1948 my father had a '39 Ford pickup with a V8 60.. The truck was in mint condition, probably because it was so under powered, it was hardly ever driven.. Dad had bought the truck because it was very cheap..
The V8 60 in a pickup was about the dumbest idea Ford ever came up with..
 
When I got my 37 Ford 60 I already had a Columbia axle ready to go on a 3:78 gear. I had rebuilt for an aborted 39 Ford project and really wanted to use this overdrive in my coupe but the V8 Club Columbia guy explained that it would not work very well. I ended up using a later engine I had ,39 transmission hydraulic brakes etc. I am very happy with the way it cruises. I always wondered if anybody ever had any luck with a 60 hp 4:44 and a Columbia either back in the day or now.I doubt if back in the day because the 60hp were usually bought by very thrifty people that would not pay extra. A couple years ago there were some Fordbarn post about a guy driving a 1939 Ford to Saratoga New York meet,60 hp and a Columbia and sounded like he liked it pretty well,only one I ever heard of. One great thing about the 60 h.p cars I have noticed over the years, usually the same pedigree of owners when bought new,like mine no radio ,no heater,basic transportation for a former Model T or A owner. The neatest thing is they took care of the car or only drove it occasionally and that is probably why when I was looking for a 37 most were the 60 .
 
BluCar No the 4 cylinder was worse. I asked a guy at the Hiawassee Ga. meet that had a 4 Cylinder P/U how it was. He said worse than a 60HP. G.M.
 
Man wanted to know about a Mitchell in a 60 pickup. How many actually tried to answer his question? Good Luck: Fred A
 
Well...to develop the thinking...print off some graph paper from the many online sources.
Using 29 tooth type ratios and the 4.44 rear plot RPM vs road speed in 2nd and high gears, then plot the same with the available OD ratios...You want to keep the thing in between torque peak or at least at the fat part of that curve in the Ford dyno chart and around the power peak. Any ratio that gets you too far down the torque curve will not be good in a 3,000 pound plus vehicle with this little engine. I suspect that 2nd and 2nd overdrive might be routinely useful as 60's had problems with hills in stock high gear...
 
It is probably a little known fact that the Railway Express, (an earlier version of UPS) trucks in 1939-40 were 1 ton Ford vans with V8 60 engines.. These trucks must of had a gear ratio down in the 5's..
 

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Having said that...

Flat Ernie said:
I'm sure you did the math already, but a 28% OD ratio with a 4.44 rear is about 3.19
Click to expand...

Looks like a pipsqueak engine may have a tough job pushing that pickup along with any commonly known overdrive. Perhaps there is a T5 variant that would work. My open wheel Model A/60, at 800 LBs lighter may just get by. I have some seat of the pants experience with my T that just had the Model A rear axle at 3.78. Good Luck: Fred A
 
Did anyone consider the torc? V8 60's have a flat torc curve. 95ft/lb starting at 500rpm through the RPM range. Torc is what's going to pull that over drive right? My math says at 50MPH I will run 2700rpm. When I turn on a 36% OD I will be running just under 1700rpm with 95Ft/lb of torc. Any thoughts?
 
I don't think you'd pull it at 50mph, but you might at 70mph...because there's also a HP issue in the mix and the weight of the car and are there any hills and... Yes, torque moves cars and HP is derived from torque, but those are both oversimplifications of what's going on.

Or, try a shallower overdrive. ;)
 
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