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How fast can you go???


buckaroo

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ssues Hello and thanks for letting me join your group. There is so much good info here to help me with my first project.

So here is my question. 3 weeks ago I bought a 49 1/2 ton dodge it is in realy good confront and all original ( to my knowledge) it has a 218 with 4 speed tranny. I have changed all the fluids, new plugs fuel pump and filter plus new wheels and tires. I have been talking to some folks on Facebook. They are saying there top speed is the upper 60s low 70s. I can only hit 55 in mine.it seems to have plenty of power and runs and drives GREAT burns no oil and has no misses. I was going to do the jeep axle swap but want to know if there is other mechanical issues I should be looking into first. Thanks for the help

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Got up to 55 going down a hill with the engine screaming. And I have over-sized tires in the rear. I also slowed down as soon as I could as it was pretty scary.

 

'53 1/2T B4B / 218 / stock 4:10 rear / three in the tree

Pretty sure these were designed for about 45 comfortable.

Edited by TrampSteer
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I'm not worried about going that fast it drives outstanding huge difference after new tires and wheels everything is tight. But I have to drive it 1500 miles back north and would like to do it a bit faster then 55mph

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I've had my 52 truck up to 75mph , but it appeared to be working a fair bit at that speed. The engine is 218ci (bored 60 thou), diff is standard 4.1 ratio, and tires are 6.50 x 16. I prefer to cruise along at 45-50mph as the engine seems more comfortable with that speed.

My 53 truck should do it easier (than my 52) as it will be fitted with a 3.54 ratio diff.

Edited by Desotodav
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Check your tire's mounted diameter (should be on the tire manufacturer's website or you can measure it) and your rear end ratio and then plug it into a calculator to see what your engine RPMs will be. For long engine life you will want to keep your cruise RPMs no higher than 3200 to 3300. My calculator is at http://www.ply33.com/Misc/speed#calc

 

With stock tires and stock 4.375 rear end, my long distance cruise speed on the freeway if I want to get somewhere is between 60 and 65. I've had it up to 70 as indicated on the GPS and while the engine seemed happy it was definitely pushing the limits of my 81 year old design suspension. Back roads at 45 to 55 MPH are a lot more fun than the freeway.

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110 no problem, get rid of that 4.11 rear end, and go with more highway friendly gears , or a T5 overdirve set-up.

How fast do you want to go BTW, if your looking for speed and power, flatheads might not be your ticket, but smooth reliable cruising you can expect. 110 kmh that is......LOL

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Trampsteer get rid of that 4.11 rear end, and fix your front end, and you will cruise 60-65 mph no problem, 45 mph is downright dangerous on most highways these days..

Tod, that 33 must be screamin in pain at 65mph plus, with that gearing...

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Tod, that 33 must be screamin in pain at 65mph plus, with that gearing...

 

65 MPH works out to about 3600 RPM which is what the factory engineers did their 50 hour tests at. Except that they had the dynamometer set to require max brake HP and on the flats I don't need full throttle. Normally I back it off to a little above 60 (about 3200 RPM) as I believe that is better for the engine for long term operation.

 

And all of that is when the freeway is the only option to get where I want to go. Back roads at 55 MPH or less is the sweet spot for the car.

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Buckaroo, 

 

45 mph is about comfortable with a 4.11 differential (even with larger than stock tires). You want your engine to last as long as possible and you certainly don't want to throw a rod and go on a willdgoose case looking for another block to rebulld. Our trucks have a high center of gravity, Model-T suspension, old fashioned drum brakes and steering boxes that in most cases have seen miles of bumpy back roads and/or plow furrows before you were born. 

 

Everyone knows that I want to drive the highway at 65-70 mph, but not without the steering (kingpins & steering box) in the best possible working shape, a 3.54 or at least a 3.73 differential and most importantly a disc-brake conversion kit up front.

 

I sure wish I had a 6 volt tachometer. 

 

Welcome and good luck with your truck,

 

Hank :)  

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If it's straight gears most any lube should be good. If it's got synchronizers, GL1 is what you need. NAPA can get it if you don't find it on the shelf.

My 48 B1B might do 60 4:11, slight oversize tires, would be screaming. I can't imagine it staying together long at 65.

I one had a 40 plymouth. Not high mileage, good motor. I get into a road race with someone, pushed it about 70 or a bit more for about 15 miles. Had to stop when a rod bounced off the frame.

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Buckaroo;

 

I believe there are several things you should consider when putting one of these trucks into use in modern traffic conditions.

First and foremost you should never assume that the people you share the roads with will make any allowances in the way they drive just because you are driving a vintage vehicle. Some might .... but others couldn't care less and will make their driving decisions as they always do. What this means is your truck needs to be in tip top shape and perform as close to the way a modern vehicle does as is possible. How far to take this is really up to what the driving conditions are in the area you intend to use it.

 

There has be a ton of discussion here on the various mods required to raise cruising speeds. Rear end swaps are certainly the easiest. Because of the traffic in the area I live in......Los Angeles Basin.....I chose to go with a 3.55 Grand Cherokee rear end with 12" discs. I also added a Rusty Hope front disc kit along with a M/C  from a Grand Cherokee. For me this set up made the most sense. Acceleration and cruising speed is fine and the 4 wheel discs can slow it down very quickly indeed. This is a must to operate safely here. You should also do a complete inspection of the suspension and steering. It all needs to function as it was designed to and new shocks and radial tires are a big improvement.

 

There are lots of other items you should consider as well. Lighting and seat belts to name a couple. And of course making certain of overall reliability which should be at the top of all of our lists.

 

Jeff

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thank you guys for the info it sounds like im headed in the right direction I have put new tires and wheels and shocks they made a huge improvement on the drivability.iam the second owner of this truck it was originally owned by and old man in my home town that took very good care of the truck. it drives and handles damn near better then my 2000 dodge 3/4 ton so im not scared to take it a bit faster. so this mounth I will do a rear end swap with some 3.55 and brake up grade. but if there is anything else I should not look past please share info like I said right now my top speed is 55 mph  others are claiming faster like high 60s that's y I was asking because I thought I might have something else wrong  thank again for the information and keep it coming I will take all I can

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Bucaroo - my advice will differ from most of the posts above.  First, decide what kind of driving you'll do most of the time AFTER you get back "north".  Then decide if all the mods described above are necessary for that kind of driving.  I do not disagree with any of the recommendations above IF you need a safe, reliable Interstate cruiser.  I do recommend the front disc brakes because unpredictable drivers don't confine themselves to the 4-lanes.  I bought, but never installed a 3:55 Dakota diff to replace my stock 4:10 gears.  The truck almost never gets driven faster than 55 mph, and with the 4:10's (and a non-syncromesh 1st gear) I find that city driving is enhanced due to the ability to take corners in 2nd gear.  One side benefit is you also get a lot of engine braking with 4:10's to help the front discs stop the truck.  You could rent a U-haul trailer and haul the old truck home.

 

You mention that 55 is your top speed - it's possible that your axle ratio is even higher (numerically) than 4:10.  I don't know specifics for the 1950 trucks, but my 1955 came with either 4:10 or 4:86 ratios.  Do you have a tachometer installed or temporary?     

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Several years ago I used my '38 RC as my daily work commute vechicle, 125 miles a week, mostly on I-5 between Auburn Wa. to Tacoma Wa. Running a '57 Plymouth 230, stock 3 speed and a 3:78(I think) rear, anything above 55mph was a struggle due to engine rpm's and stock suspension. That stretch of I-5 also has a pretty rough surface due to heavy semi traffic. I just always drove at the speed I felt most comfortable with, usually 50 to 53 mph.

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I had my 49 1 ton out last night to a cruise, and it runs good at about 45 with the 4.3 rear and 6.50-16's dual on the rear.  I'm planning on going to 7.00-16's over the winter that will raise my cruise speed only slightly.    I have a 78 Dodge D100 that I've had for 33 yrs with a slant 6 and 3.55 rear running 215/75R-15's.  The 3 speed is 1:1 in high gear, and at 60 she's starting to wind up.  I've had it up to 70 to pass on an interstate, but I wouldn't leave it there any longer than I have to because of the high rpm's.  I have calculated the rpm's in both vehicles using the rpm calculator, but I'm going by my ear and gut.  I've rebuilt both of these engines once (I got 150K out of the slant before it went), and am in no hurry to do either one again.   You might do 70 for a short time with a flattie and a 3.55 rear, but I don't think you'd do it for long at least from what I've seen.    Mike

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Edited by MBFowler
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I have a 3.0 rear and a 1950 Chrysler 251 in Old Yeller,my 52 1/2 ton. She does fine on the freeway but the brakes are stock drums so I like at around a mile a minute.

So if you are traveling 80 MPH how long does it take you to drive 80 miles?

 

Click here>>>>  http://www.youtube.com/watch?v=G8DNGh126oM

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My top speed is 150 mph.  

 

I use 110 Octane, hand signals, and GPS.

 

That's how fast I go....maybe faster next year.  

 

48D

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