Mitchell 26% or 36%?

[1929]

I have a 29 coupe with a touring engine, a 5.5 Snyders head and a 3:78 rear and I find that to be just right with the Mitchell 26% overdrive. I think it may lug too much with the 3:54 rear especially in my area which has some rolling hills. On the flats it will easily run at 60mph but the wheels, steering and brakes being stock I feel it gets pretty twitchy over 55. I would recommend a smaller/wider tire, short pitman arm and cast iron drums if I ran over 60mph. Don't forget this is still an OLD car.

I will be switching to the smaller tire. I have the short pitman arm and the cast iron drums, many new improved parts for safety. What would you recommend for mostly flat terrain, 26 or 36 for my 29 coupe with a touring engine.

 

[Barry B./ Ma.]

The 36% should be OK in your case for mostly flat terrain, just don't lug the engine as its not good on the babbit bearings but I have never driven a Model A with that combination and I'm happy with the 26% I have.

 

[TerryH]

Where I live, I drive a lot of surface streets, where the speed limit is 45 mph. The Mitchell is so easy to use that I usually shift into OD when travelling on those, even with traffic lights. But 40 mph with the 26% is a out a slow as you would want to use it, on flat ground. Seems to me that a 36% would only be useful if you are going over 50. I love driving mine at 45 in OD......it is amazingly quiet and nice.

 

[1929]

The 36% should be OK in your case for mostly flat terrain, just don't lug the engine as its not good on the babbit bearings but I have never driven a Model A with that combination and I'm happy with the 26% I have.

I had the engine done with inserts.

 

[daveymc29]

1929, with what you have, I believe I'd have to stick with the 26%. I believe you would be able to use the OD more and to better advantage. 2nd gear in OD will pull your hills fine and I'm not sure the 36% would unless you changed to the 600/16 tires. Then you could probably use it handily. On truly flat terrain it would work as is, but would probably get lugged on hills of small incline and I have been cautioned all my life about lugging Fords. If you are diligent about retarding the spark on long pulls it will probably work. So what I'm trying to say here is it will most likely work if you drive it as Mitchell recommends.

 

[1929]

I received a call today from Steve Mitchell and his recommendation was to keep the 3.78 and go with the 36. He has been in the business for over 30 years, I guess I have to value his opinion.

 

[Slowplane]

In the past month, I've put 300 miles on a fresh, complete overhaul of a '29 station wagon that had sat since the 70's. It has a 36% Mitchell w/3.78, and a 6:1 touring engine. I'm pretty gentle with it during break-in, and it handles the hills around San Diego County fine so far (tho' I haven't taken it up into the mountains). I think it'll work out.

 

[modelAtony]

I have 31 Tudor been running 3:27 rear with stock engine since 2001 , 2003 for Great Race added 26.7 Mitchell, 5.9 Brum. The performance blew me away. 2008 added inserted engine , Jim Brierley cam , took off 25 lbs on flywheel and mounted web carb. Dyno 65 hp @ 2900, 60 mph @ 1800 in overdrive, top end speed 96 mph . running 63-64 mph avg 21 mpg. Mileage per year normally around 15,000 . This engine was built by John Cosper from Pete's Automotive in Alb. NM . the 3:27 and 26 Mitchell with a little add on stuff will be a great performer. Have fun modelAtony tony white Lafayette, LA

 

[1929]

According to Steve Mitchell, you can easily change the gear in a Mitchell overdrive on your own and change from 26% to 36% or the other way around. Therefore, if you buy a Mitchell overdrive with the wrong ratio for you, then you are not stuck with it.

Just call Steve and tell him you want the other gear ratio. He will send you the parts.

I took your advice and did receive a call from Steve Mitchell yesterday, his recommendation was the 36% with my 3.78 .