The Stovebolt Site Forums The Parking Lot Big Bolts 1946 2 Ton 216 4 Speed: How To Increase The Top Speed

Change rear end gears, overdrive transmissions, and, auxiliary over drives.

Truck has the 2 speed rear and from what I read there is no way to change those gears.

Now if I got a single speed rear from a 1.5 or 2 ton truck are lower ring and pinion gears available?

Are there any overdrive transmissions that are a simple bolt on?

Are there an auxiliary overdrive units and are they simple to add on to the truck?

I have one of those trucks. It tops out around 50. I have had it up to 55 once or twice, but it was a little scary. These old trucks just weren't meant to go fast. Even on the best roads around, the steering is kind of vague over a certain speed. The brakes are fine at 45, but at 55, not so much. And that's running empty. With a load on mine, I stick to the side roads and take my time.

My son plans on using the truck for his catering business. Most of the times he will be doing 35 to 45 mph.

Though there will be times when he will be on highways where they will run you over if you can not do 55.

So if can bolt on an overdrive unit behind the transmission and have a new driveshaft made he will of picked up some speed for the highway and by keeping the original driveshaft untouched and put away the truck can be easily returned to it's original condition.

I ask this question when I first got mine on the road as well. There are a number of things that must be done before you think about going faster.. Brakes must be upgraded. These trucks were not meant to go fast. They simply do not have enough power behind them. I use a 46 2-ton for my business. It gets plenty of weight on the back. Empty I can run 55.. Pushing it to low 60's every once in a while. I am still running the splashed 235 4 speed trans and single speed rear end. I did however make disc brakes for the front. It stops and stops well.

Don't expect highway speeds without upgrading the stopping power first! Then you will need to increase the power just a little bit, then figure out gearing to accommodate!

What did you do to get more power?

I was able to run those speeds before my engine build. When I tore it down it had standard bore pistons in some very sloppy holes... 20 over at the bottom and as much as 40 over on the top. After the rebuild it does run much better, but I didn't gain any speed, just a little quicker getting there. No upgrades at that time. A good bore job and valve job. Careful assembly.

Check everything. Timing, valve adjustment, carb, plug wires, plugs, points, etc. Make sure everything is operating as it should. Then make sure you can stop that thing.

I do run 8.25 tires on the back as well. That also helps a little with top end. Also know that your speedometer probably isn't accurate. Mine reads about 12% slow.

Our speedometer does not work. We just found that out after we got the truck running again.

I disconnected the speedometer cable from the back of the speedometer because I thought maybe lubing the cable would help.

I found that there is no cable in the housing. So I ordered a new cable and housing. Hope that is all it needs.

A GPS can be a very good addition instead of trying to make a 60+ year old speedometer work accurately and reliably. If you're still running a 6 volt electrical system, a small 12 volt motorcycle battery will power a GPS and a pretty good entertainment system for several days between recharge sessions.
Jerry

Bigger rear tires would be the easiest way to get more top end speed,I have 20 x 7.50s and I only get about 45 MPH with a rebuilt 62 235. These trucks are very low geared, especially with the 2 speed diff. If you go to a 20 x 9.00 you'll gain 10 percent, about 5 MPH.

Well being my son just bought new 7.50 x 20 for the fronts and 8.25 x 20 for the rears we will have to wait awhile before we can try larger tires.

Going from a 38" dia. to 40" dia. at 50 mph will increase speed 2.63 mph and at 55 mph will increase speed 2.89 mph.

If that engine is original to that truck, it would be a Loadmaster 235, instead of a Thriftmaster 216. 216's were standard in 1/2 ton thru 1 1/2 ton. 235's were standard in the 2 ton trucks.

I have followed your posts and thought what Spanky just said. Even my mechanic, who grew up in a Chevy dealership, thought the early 235 was a 216 because of the side cover. The first 235's look like 216's, check the engine serial number to be sure what you have.

And your speedo will indicate the speed with the original tires if correct then.

Well you made me happy. We can brag that we have 93 HP instead of 90. For the engine is suppose to be the original. I'll have to check for the engine casting numbers.

Where should I look for the numbers?

I know there is a number stamped on the block next to/just rear of the distributor. Though I will not be able to look at the truck for a day or two. For my son took it out east for the time being.

Anyway I followed my son today as he drove out east or as they say drove down island heading out to the North Fork on I 495. The truck hit 53 on level grade and he still had some pedal left.

He was also able to hold most grades doing 45 and again he had some pedal left. He was smart to not push it flat out on his first high speed distance run. Went about 75 miles.

Edit to add: Previous to us owning the truck someone had taken the throttle plate off of the governor.

Sounds like it was a good trip. I was just on Long Island this past weekend, lots of courage to take I495 out. Your son live out near Riverhead?

Traffic was light because it was a week day and the time of day. He first lived in Greenport and now he is in Orient.

Have you been to the island before?