The Stovebolt Site Forums The Shop Area Engine Shop top speed 70mph with a stock 1 ton ???

my wife was following me on the interstate, and wasn't keeping up with me. I asked her why and she said it's a 65 mph zone and I was speeding. I didn't know as my speedo doesn't work. but that made me wonder: am I supposed to be able to do 70 with a 1959 1 ton? as far as I know I'm all stock (except for the alernator).

How were you doing with other traffic? Around here you will get run over doing the speed limit and I would estimate the general public runs at least 5-10 mph over the limit. Just because she was in a newer car doesn't mean that her speedometer is right either.

a 1T with 5.14 gears and a 235 would be pretty much screaming and you'd be pushin the pedal hard to the floor unless you were on a long downgrade .... I'd suspect the car speedo too, but might be worth checking the actual rear ratio, they came out with "fuel saver" ratios for the 1/2T in 58, might have had better gears for the 1T as well, or you might actually have the 3/4T 4.57 rear

Bill

How tall are your tires? With your tire height and gear ratio you can calculate speed at RPM using one of the online calculators.

70 with the stock gearing and tires with a 235 seems pretty fast, but I would not say its impossible.

Time yourself over a measured mile at a relatively steady speed. 60 seconds for one mile = 60 MPH. For other speeds a little simple math will get the job done. For instance- - - - -a 50-second mile would compute as follows: 60 divided by 50 = 1.2 miles per minute. 1.2 X 60 = 72 MPH. A 70-second mile = .85 miles/minute, or 51 MPH.

70 MPH, unless you've got the extremely scarce 4.11 ratio rear end gears, would be a stretch with a 1-ton with normal-height tires. My 59 model 3800 dually with 18" wheels had a hard time maintaining 65 MPH for very long.
Jerry

just check it with a GPS.

'Tater will do 60 on level ground, and that's with a bone stock 270ci L6, SM-420, 8.5:1 (in high), on 8.25x20 wheels. I try to keep her around 55 so I dont start ejecting random parts. :P

Had my old 3/4 ton runnin 16.5" wheels and a 5.3ish:1 rear end that would roll at 80 all day long without issue. RPM's were up around 5K, but it was a 327 V8 pushing thru a 4-speed car trans.

If it has 17" tires, 70 mph is not all that fast. In 1962 Texas raised the speed limit from 60 to 70 and of course had to lower it to 55 in the mid 70's. We drove the speed limit and more in those days. We just disregarded the noise and vibrations. Engines don't fly apart when operated in the 3,000+ range, even though they may sound like it. As long as you have a good radiator to keep them cool, a stock carburetor won't give them enough gas to over rev them to dangerous levels. For us old geezers who got their drivers license in the 50's, having to slow down to 55 in the 70's was a real pain.

I guess the absolute answer is still up in the air. I've done the milemarker timing, and I've passed other cars on the interstate. I do have 19.5 tires. I'm not even flooring it completely. And the only breakdown I ever had was when I had a major vacuum leak combined with a clogged radiator which led to a piston with a dime-sized hole in it. Since then I got a new radiator and flushed the whole system, and the oil has always been clean. I guess it may just be running really well

The 19.5 tires are part of the answer. Your tires are quite tall. If you can measure the height of one of your rear tires you can use that and assumptions about what rear gears you have to estimate RPM at Speed.

If I had a height for a 19.5 I'd already have those numbers in a table in this reply.

hey I see some of you mentioning even size tires (17, 18) for the Task Force trucks. aren't the even numbers split rims and the odd (like my 19.5) 'normal' rims? I thought all TF trucks had regular rims??

best idea- have a gps in one of my trucks, its actually easier to see the speed than looking down at the cluster, plus since the tire height was changed the speedo is off, and i only noticed it by the gps. only off by about 4 mph, but enough for a cop to ticket me (if he is an a-hole). but yeah, gps is best.

If curious what the gear ratio is why not jack up a wheel, count some turns, and do the math??

Grigg

I've had my '62 1 ton to 70 mph on the flat and downgrades but it did not sound happy so I didn't keep it there. It has a 235, 5.14 gears and 7.00 X 18 tires

To my modern ears accustomed to very quiet motors and even quieter cars, I suspect what sounds like its about to fly apart is really nothing more than working it a little hard.

What limits my speed is the old suspension and steering more than the motor.

I wouldn't push a babbit motor but remember guys used to race those against flathead Fords back in the day.