Speed Limit
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Speed Limit
Thanks to the re-manufactured generator I just put in my 56 F-100 it is back on the road again. I'm wondering what a safe highway/freeway speed for this truck is so I don't overdo it. It has the stock 272 and 3 on the tree in it. I've never driven over 30 mph before but it runs strong and I would like to take it into town. I'm thinking around 55 might be it's max. If anyone has any input as to how to avoid abusing my engine on the highway I would appreciate it. Thanks in advance,
Mike
Mike
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My 56 is a 272 Y-block and 3 on the tree, but I have a 3.73 rear gears. Mine drives out really well. The front end is tight and the the steering is as well. I run 60 in mine with no problems.
I would guestimate that I am turning about 2500-2700 RPM at that speed.
I could barely hold her in the road at 40 until I got different tires. It shook really bad with the old ones.
Read this thread I started where I had a similar question:
https://www.ford-trucks.com/forums/s...highlight=tach
I would guestimate that I am turning about 2500-2700 RPM at that speed.
I could barely hold her in the road at 40 until I got different tires. It shook really bad with the old ones.
Read this thread I started where I had a similar question:
https://www.ford-trucks.com/forums/s...highlight=tach
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From: Littleton, New Hampshire
Originally Posted by microb
Checked the door plate and it says its 3.92. So should I be safe at 60?
Vern
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From: Central PA
My '54 F-100 has the 239 Y-block with the 3.92 rear end. It will go 60. It will go faster but you shouldn't for a long time. How accurate is your speedo? It is best to use your ears and listen if you are winding it out. 55 is safe, then you still got some room to speed up for passing or showing off for when that rice burner car tries to pass you!
abe
abe
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Thanks for the input everyone. I'm not trying to race this truck or push its limits. I just respect the past care that has been taken to allow me to drive this 50 year old truck today, and I want to be sure that I continue to treat it as well as the previous owner.
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From: Minnesota
http://www.classictruckshop.com/garage/shopmathrpm1.asp
This is the way to tell what rpm you will be turning. You know you have 3.92 rear end gears, the transmission has 1:1 high gear ratio, I do not know what you have for a tire height so you will have to plug in the numbers.
This is the way to tell what rpm you will be turning. You know you have 3.92 rear end gears, the transmission has 1:1 high gear ratio, I do not know what you have for a tire height so you will have to plug in the numbers.
Fleet Mechanic
Joined: Jun 2004
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From: Minnesota
Try this link, and by the way if two other posts show up it is becuase I got some warning message about posting a link to the Clasic Truck Website that I go this from the first time. The high gear ratio is 1:1 for the three speed.
http://www.westerndiff.com/rpm.html
http://www.westerndiff.com/rpm.html
Last edited by Christopher2; May 28, 2006 at 08:51 AM.
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I went to the auto parts store and bought a cheap tachometer. I thought I had it figured out until I read the past two posts and both calculator links told me that at 60mph I should be at just over 2700 rpm which isn't too bad except my tach is reading 3000 at 40mph and 5000rpm at 50 mph. Could the cheap tach be to blame here or what? I have serious doubts that the rearend has been changed to lower gearing than what came stock in the truck. By the way thanks for the trans gear ratio.
Mike
Mike
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Okay I assume with the calculators when it asks for tire height that would be the diameter of the actual tire and not rim size. When I plug in rim size the RPMs come closer to what my tach was reading but I'm pretty sure that it is asking tire diameter to figure tire circumference for tire revolutions not the rim. Does this seem right? When I momentarily took it up to 50mph it sounded like the engine was definately working but 5000rpm seems more than what I would have guessed based on my ear. I'm having a difficult time due to the fact that I am used to hearing my 4 cylinder "go to work" car that I normally drive. I know that I can definately tell when my Focus is hitting 5k. My ear is not quite in tune with this engine though I'm thinking its not actually reving THAT high.