Cruising speed stock 47

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PKW181

Member
Wondering what is a good cruising speed for a 47 Ford coupe, with a stock flathead would be? Maybe 60-65 mph?
 
If all mechanicals are in good condition.

I have driven a bone stock 47 Tudor and at 55 it sounded like the motor was wound out to the max. It wasn't mine, so I did not push it any further, but I'm sure it had some reserve.

I would think it has a lot to do with the rear end gearing and weather or not it is equipped with some sort of overdrive, or a two speed rear axle.
 
May not be quite the same, but my '51 with 3.55 gears and no overdrive is "happy" at 50 (2200 rpm) and at 65 (2800 rpm). It like to "sit" at those speeds, but really not in between. I have no idea why.
 
PKW181 said:
Wondering what is a good cruising speed for a 47 Ford coupe, with a stock flathead would be? Maybe 60-65 mph?
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I think you are pretty close if the engine, suspension, and brakes are in good shape. If you drive it a while you will find where it is happy.

I understand that many of the '46/'48 cars had 3.54 ratio rears in them. You should find some numbers on the flat portion of the rear end housing between the torque tube and the bottom of the housing. Divide the larger number by the smaller number for the ratio.

My '38 has a 3.78 rear and 8.20 x 15 (29.3") tires. I am comfortable around 60 with it.
 
I drive our '47 tudor with stock drive line and suspension with 3:78 rear at 60 mph easily. I have had it wound up to 70 mph too. 60 is where I like to cruise at.
 
Ford gave Columbia Overdrive a lot of business until the end of the banjo production in 1948. Borg Warner R-10 overdrives followed that for folks that wanted to go 65 or 70 all day long.
 
My 41 has 4:11 in standard drive and 2:94’s in overdrive, (Columbia). At 65 mph the engine turns 3500 rpm in standard drive and in overdrive 2500 rpm. I can comfortably drive at 65 mph or faster all day long.

My 36 has the same gearing and drivetrain setup and it runs in the same RPM ranges. However the car feels like the engine and car itself is racing at 65 mph even in overdrive. I think it’s the shorter wheel base and the suspension that feels limiting.

Your 47 is a heavier car with so it should ride smooth enough and as long as the engine RPMs are less than 3000, I would think you would be fine. I would go with what feels comfortable.


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In JWL's book the flathead reaches peek HP around 3200 Rpm however the max torque is in the low 2000. I feel the cam is the limiting factor. Ford had a cam change in 52, but I have no idea where the peek torque is now. My 280 has an EAB cam and 3.73 with OD. It does have a massive amount of torque, but runs out of revs around 3500. The OD rund great around 2500 at around 60 +. probably should have put in the Max #1
 
Hi Everyone. I have been accused of having a bit of a heavy foot. I don't do burnouts or such, but I don't mind keeping up with traffic.

Didn't I hear that the advertising said the flathead would go 80mph right off the showroom floor?

So, when we got our very stock '36 Phaeton around 2008 it was wound up at 55mph, seemed like it was all done. It had 4.11:1 rear ratios and loved to see a hill in front of it, gobbled 'em up.

Charlie Schwendler, known here as CharlieNY, fixed up with a sweet 3.78:1 replacement rear. The difference was very dramatic. The same car now easily does anywhere between 60 and 70mph, and I've had it up to 75 on I-72 between Decatur and Springfield on the way to the 2014 EFV-8 Central Meet put on by 'Barner Kens36 and his great wife Carolyn and their huge team. We had an amazing time driving route 66 and visiting a lot of Abraham Lincoln oriented locations!
 
The engine can probably live through most torture tests. I think somewhere around 60 is comfortable even though I have Lincoln brakes and front and rear anti-roll bars and a Panard Bar and Mitchell overdrive and radial tires.
 
I just don't believe you can spin the Flathead V8 RPMs up enough to do damage. This engine can't breathe that much air in and out. Look what Clyde Barrow and John Dillinger did to these V8 in 1933-34 sedans on 1933 roads. They put the entire car through the ringer. You didn't see these guys wasting time with a stove bolt 6 GM product. You better believe they had the cruise set at 70+ mph when on the run. They didn't stop to ponder the rear end gear ratio either.
 
As long as you have a load on it, it will run out of breath long before you hurt it. You might do some damage sitting in your drive way and holding it wide open. Why would anyone want to do that? I've run my '48 70 mph and above on the interstate for years. Still going strong.
 
Seth Swoboda said:
I just don't believe you can spin the Flathead V8 RPMs up enough to do damage. This engine can't breathe that much air in and out. Look what Clyde Barrow and John Dillinger did to these V8 in 1933-34 sedans on 1933 roads. They put the entire car through the ringer. You didn't see these guys wasting time with a stove bolt 6 GM product. You better believe they had the cruise set at 70+ mph when on the run. They didn't stop to ponder the rear end gear ratio either.
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Ryan did a good article on the HAMB a couple of days ago on hopped up cars and the gangsters of that period.A good read.

I have an 8rt (stock)in my 30 coupe ,duel carbs on a Almqiust sling shot intake,39 trans with later gears and 7.54 rear end.The car is light 2100 lbs all wet with me in it. It absolutely loves 2nd gear and will cruise at 65 mpg at about 3200 rpm.It will go faster ,but things start to rattle and shake(bias tires).
PS,it does the 1/8 mile in 12.3 seconds at 53.5 mph,not fast but fun.
 
Thank you everyone for all the info.
I have been looking at finding a 46-47 stock Ford driver either a coupe or 2dr nothing fancy just one to drive and enjoy.
 
PKW181 said:
Thank you everyone for all the info.
I have been looking at finding a 46-47 stock Ford driver either a coupe or 2dr nothing fancy just one to drive and enjoy.
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If you want an affordable way to get into this hobby in a car that makes a good driver for touring, you can't go wrong with a '42-'48 Ford.
 
Ol Henry should chime in here,
our 33 with a 3.78 rear will go all day at 60mph,(99a engine)
lawrie
 
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