C50 Owners
 

Am in the process of restoring a 1964 C50 for a tow rig. It has a 292 L6 four speed and crazy low gear rear end... Top speed seems to be about 40 mph. Wondering what others experience has been. https://photos.app.goo.gl/8Qzh3wEiBKvNmZrN9

Re: C50 Owners
 

It's all a function of ratios. For an old tow rig, especially with a 6 banger, having a low top speed in return for having the pulling ability to tow is the trade off. Remember, when this was built, speeds were lower than they are today.

Only way you are going to get better top speed is to add an overdrive of some type and/or change the rear gears.

Re: C50 Owners
 

Is the rear end a single speed or a 2 speed? Back when I used to drive my '63 C60 with a 292, 5 speed and 2 speed rear, I had no problem cruising 55-60.

Re: C50 Owners
 

Mine is a Single speed rear with a four speed manual trans. Going to get a tach so I can see what kind of RPM this beast is turning. Torque is excellent because of the long stroke. What would be a reasonable max RPM for this engine? https://photos.app.goo.gl/wGBwtQPpcXrxiZXN8

Re: C50 Owners
 

looks like I have a 7.2 to 1 gear ratio which would explain the RPM / top speed
https://www.gmheritagecenter.com/doc...olet-Truck.pdf

Re: C50 Owners
 

Hi Timbercraftsman, I have a 66 l60 with 292 and 4 speed no 2 speed and 22.5 wheels,I have hit 60 on GPS but 45 seems to be it's happy place. Not sure a 2 speed rear would get any more speed just a lower range, not sure of all of our options but after a wicked panic stop with no bed on my truck I am happy for now,I am going to follow your thread, Pat

Re: C50 Owners
 

The 2 speed rear you would want has 7.95:1 low and 5.83:1 high range so you would have better off line power and higher cruising speed at same rpm as current 7.2:1. Looking at numbers online they also made a 8.72:1-6.4:1 rear but that wouldnt help your rpm as much. a 2 speed trans behind current 4 speed is also a option if you can find one.

RPM difference with the 7.2:1 to the 5.83:1 is around 600rpm @45mph and 800@65.

If your only after a few rpm drop and are happy with off the line power then you might be able to just step tire size up a bit.