354 Ring an Pinion

[tomscott]

Hello all
I am considering changing from a 378 to a 354 rear end
In my Tudor sedan. What are the positives and negatives
Of the switch ? Is it worth all the work involved to make the change ?
Thanks Tom

[J Franklin]

If you drive in hill country you may not like having to shift down so often.

[Pete]

Originally Posted by tomscott

Hello all
I am considering changing from a 378 to a 354 rear end
In my Tudor sedan. What are the positives and negatives
Of the switch ? Is it worth all the work involved to make the change ?
Thanks Tom

Your car will go 65 mph all day as it is. If you want to cruise faster, go for it.
If you add a 7 to 1 head and a touring cam you will be enjoying as much fun driving as can be had with your clothes on.

[Synchro909]

Tomscott, what year is your car? If it has 21 inch wheels, you can get the same overall gearing by fitting 5.25X21 tyres - about 5% higher. They are 6 ply rated so the walls are thicker and they are more stable in say, a cross wind. A pair of tyres will be cheaper than a new set of gears apart from all the extra work and if you don't like the higher gearing, changing back is easy. There will be someone willing to buy your 5,25 tyres.
All of that said, A Tudor is not the lightest Model A body so you will really notice the difference unless your engine is above original specs. IMO, a 6:1 head and a bigger carburettor is enough to get the extra oomph you will need. A hotter cam comes next.

Pete, with respect, I cannot possibly agree with a Model A doing 65 all day - certainly not if you want the middle main bearing to survive the trip. For a long engine life, not much over 40 mph is all it is good for. Don't ask how I know!

[Pete]

Originally Posted by Synchro909

Pete, with respect, I cannot possibly agree with a Model A doing 65 all day - certainly not if you want the middle main bearing to survive the trip. For a long engine life, not much over 40 mph is all it is good for. Don't ask how I know!

Just quoting factory as delivered specs.

Just remember, STOCK factory babbit bearings used to go 500 miles at well over 100 mph on dirt tracks.

[Synchro909]

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Originally Posted by Pete

Just quoting factory as delivered specs.

Just remember, STOCK factory babbit bearings used to go 500 miles at well over 100 mph on dirt tracks.

100 mph in a Model A????

[Pete]

Originally Posted by Synchro909

100 mph in a Model A????

Have you not heard of Ed Winfield????????

[ursus]

Originally Posted by Pete

Have you not heard of Ed Winfield????????

Probably a previous owner of all the cracked A and B blocks I have acquired over the years.

[Synchro909]

Originally Posted by Pete

Have you not heard of Ed Winfield????????

I assume he is associated with the Winfield heads but other than that, No.

[jeepguy1948]

You can’t use both 3.54 gears and an overdrive, it’s too much for the banger to pull

[alexiskai]

Originally Posted by Synchro909

If it has 21 inch wheels, you can get the same overall gearing by fitting 5.25X21 tyres - about 5% higher. They are 6 ply rated so the walls are thicker and they are more stable in say, a cross wind.

You've been carrying the torch for the 5.25s for years. Has anyone else on FB ever tried it? Seems like a lonely crusade.

[CWPASADENA]

I have 3.25s in my roadster. They work just fine but the roadster is one of the lightest Model A's. I do not think they would be good in a heaver car unless you had a really good engine.

Chris W.

[Synchro909]

Originally Posted by alexiskai

You've been carrying the torch for the 5.25s for years. Has anyone else on FB ever tried it? Seems like a lonely crusade.

In our club, there are plenty of guys running 5.25 X 21 tyres front and back. I run them on the rear only for the bigger footprint (more grip) and longer legs.
BTW, I run them with an O/D. The resulting over all gearing is like running a 2.85 diff only I have lower ratios when not in high ratio in the O/D. I find that a bit over geared when towing. For that, I run 16 inch wheels. That brings the overall back to about 3:1

[Tanglfoot]

I have a 30 Roadster with 3.54 diff and 25% Laycock OD and i love it. My 30 Coup is 3.78 diff and 27% Laycock od and hard to tell the difference.
Cheers Rosco.

[alexiskai]

Originally Posted by Synchro909

I run them on the rear only for the bigger footprint (more grip) and longer legs.

Do you carry two spares then? Front and back?

[larrys40]

Tom, I saw your pm but am replying here as well …. I have a 3.54 in my 30 tudor, Stock engine but w/snyder 5.5 head and I run an older Ryan overdrive 23percent . It is a great highway cruiser. I personally like the 3.54 because it enables the car to cruise a little bit easier in town without using overdrive for all around use.

I think it depends a lot on your engine. Not all are created equal… helping to experiment with carb may help as well… like trying a B carb.

If running A Mitchell 26 percent on a heavier sedan I would probably stick with 3.78 but without it I would defiantly opt for 3.54. I know some of the roads in wv are mountainess but I think with a 5.5 head it will help you pull the hills better. I’m not a huge fan of the 6.1 head as it gives the engine a rumble I generally don’t like… just my 2 cents worth.

I have driven this same tudor extensively in Colorado and up pikes peak…. Million dollar highway, San Juan mountains, ouray etc…. And it had done fabulous. Shift when you need but overall I am very happy with the 3.54 and my Ryan overdrive in it.

When I finish my 68c it will have a 3.54 and mitchell 26 percent and it should do fine as well w 5.5 head. Unless I put in a Burtz and then I’m really not worried! This is a lighter car than the sedans.
I say go for it. Will you need to shift a tad earlier on a long grade, maybe so but it will be a negligible difference compared to the less rpm with it on the downhill side. I’ve restored /rebuilt hundreds of rear axles and overall I like the 3:54. I say get it while it’s available because there is a day coming these will not be available due to the demand vs economy of production/profit of making/selling them.

Happy Model A motoring ….
Larry Shepard

[Synchro909]

Originally Posted by alexiskai

Do you carry two spares then? Front and back?

No. I figure if I get a flat, I put the same size wheels on the back and the others on the front so the diff is not working all of the time. It would only be for a very short time till I mend he puncture.

[BRENT in 10-uh-C]

Originally Posted by Synchro909

No. I figure if I get a flat, I put the same size wheels on the back and the others on the front so the diff is not working all of the time. It would only be for a very short time till I mend he puncture.

So you just carry two jacks??

[BRENT in 10-uh-C]

Tom, there is an improvement as far as longevity of the engine is concerned (-due to lower RPMs at the same speed) however to fully answer your question giving Pros & Cons, the present condition of your engine factors in greatly. Most Model-A engines that I see are producing well below the rated 40 horsepower that Ford originally designed their engines to produce. Pete is pretty accurate in that a new Model-A was capable of being operated at 60+ mph for long periods. Most Model-A engines today that have a worn camshaft, or poorly sealing valves, leaking compression, etc. are barely capable of maintaining 45 mph, -much less 55-60 mph. If this somewhat describes your Model-A engine, then a 3.54 ring & pinion is not something you are going to be happy with. Even some of the so-called camshafts in 'Touring Engines' struggle due to the reground camshaft profile. On the other hand, a correctly rebuilt Model-A engine with either a new Stipe or Burtz camshaft, along with modern valves and one-piece guides will be a game changer and your Tudor will capably pull those W Virginia hills.

.
.

[larrys40]

Brent I totally agree…. The health of the engine is the major element and key. Many folks don’t realize how well they can and should be power wise when properly rebuilt, tuned, etc.

When I work in cars to whip then into shape it is a night and day difference when done.
I am a fan of keeping the rpm’s down a bit for a number of reasons. Vibration, water pump, distributor, and you can talk to your passenger better when it’s not screaming at 55-60. My town sedan engine has quite a few miles on it but still can run that easily without overdrive.
Many feel that their cars can’t do over 45…. And honestly in today’s traffic they need to on certain roads. Around here we can’t cross over the rivers without being on the highway as there is no other way.

With a healthy engine a 3.54 should be fine in just about any A in my opinion.
Larry