VCCA Home Forums TECHNICAL - 1945 AND NEWER 1946-1948 Redline for 216 engine

Looking for advice on the max RPM with a stock 216 engine. Running a '46 PU 3/4 ton w/ 4 speed. Trying to calculate a safe top speed.

Thanks!
Steve

You should be able to run all day between 45-50, just make sure that your brakes are in good shape so you can stop.

The stock ratio for a 3/4 ton truck was 4.55.
If equipped with 15" wheels the engine will be turning about 2750 RPM at 50 MPH
With the more common 17" tires it will be 2500 RPM.

Either would be a very safe engine speed for a 216 in good condition.
You could add 10% (55 MPH) to either engine speed and be safe.
The truck has a large noisey fan, no cab insulation, and no cloth upholstery to absorb noise so it will sound like the engine is really reving at a high speed in the cab.
I always used 3200 RPM as a safe engine speed for my cars and never had a problem.

Gene,

Did you determine the RPM by math using the speedometer and gear/wheel ratio or what? In other words, how do we determine our RPMs without a tach? Say for a standard 41 car at 55 or whatever that will give us 3200 RPM.

Hurts my head to try and work it out. Does too!

Charlie

I determined the 4.5 truck engine/vehicle speeds fram a graph in the Truck Data book.
Using the same for a car or truck with a 4.11 and 16" tires the RPM and 55 MPH would be about 2750 and 2500 rpm with the optional car 3.73 ratio.

OK, thanks. What in the world would be the speed with 4:11 at 3200 rpm. A little faster than I would want to sustain, I believe. I believe mine would come apart and I would wipe out half the cars around me and cause windows at all the fast food joints to shatter.

If it happened on a country road, then I wouldn't have to wait for possums in my headlights cause my mouth to water. The flying parts would kill anything within a quarter mile. There would be a new definition for roadkill. And I would have enough to fill the freezer for a month or two.

I'll just keep the sucker at its sweet spot of 40 or so, whatever the RPM.

Best,
Charlie

BTW: I think someone wrote a song called, "Oh, but there'll be a possum in my headlight tonight!", or words to that effect. Popular song up around Asheville and Morganton, huh, Chip?

With a 4.11 at 3200 RPM the road speed would be about 62 MPH. The break-in speed of a 1941 was 60 MPH after the car was driven 500 miles.
I drove my '41 out west in 1951 at 60 to 65 MPH, put on 3600 miles in 9 days.....and it had one our shops "overhaul jobs" at 75,000 miles (prior to the trip) and engine was never apart before that.

The Motor Trend test report in the September 1950 issue showed 3,000 engine rpm gave 64 mph (Powerglide with 3.55 gears) or 60 mph (3 speed with 4.11 gears). Maximum horsepower was at 3,400 rpm (92 for the 216) or 3,600 rpm (105 for the 235).
A lot of us VCCA members have driven the 216s with 4.11 gears all day long at 70 mph without any problems. Just keep the oil level at or above the add mark on the dip stick.

H Steve,

Welcome to our chat site. Please provide us some more info on you and your truck.

What the potential maximum speed is and what is a safe speed are two distinct differences. I go with Don's recommendation for good brakes, including an emergency brake in excellant working condition. You also need to be aware that at 50 miles and hour or maybe as low as 35 you and your passenger would most likely end up in a hospital in critical condition if you have an accident! Our vehicles were not engineered to any of today's safety standards yet most of us think we can drive them where ever we want, and as fast as we want! It also makes little sense to scare the hell out of your passenger if any speed related issue comes up while you are driving. This will make them leery of ever wanting to ride in your truck again.

It is also important to know how your truck will react to having its brakes slammed on at various speeds, including just using the emergency brake to stop.

Good luck, Mike

You can plug figures into this calculator, BUT you need to know your tire DIAMETER.

http://www.crawlpedia.com/rpm_gear_calculator.htm

Below is a tire diameter chart.

http://www.dbtires.com/crossreference.html

With a 6:70 x 15, and a 4:11 @ 55 MPH, the RPM is 2762.

bobg,

Thanks for the blue lit formulas.

Mike,

You take the fun out of everything. We don't think about no stinkin stopping. Just high speed and acceleration. I bet you drive with two white knuckle grips on the steering wheel, don't you?

Questions:

a. Have you ever been on the back of a four-wheeler ATV with a wild 14 year old at the controls?

b. You ever been on a speed boat with unknown bottom depth? No brakes a-tall. Oh, you'll stop alright!

c. Ever road in a pre-1936 or whatever with mechanical brakes whilst maneuvering in holiday traffic?

d. Ever been in a 1950 Olds Rocket 88 that upon holding the brakes and mashing the accelerator causing the whole body to rise up like a leopard getting ready to pounce. Some say the front tires would jump a couple of wieners and never leave any tread marks.

e. Did your dad own a 1936-48 Dodge four-door as did Richie Cunningham's dad. Bet so.

f. What do you do for a walk on the wild side. Go to the local Dairy Queen circle it a couple times whilst revving the engine like you're looking for a drag contest, then parking and having a vanilla soft-serve.

g. "Brakes? We done got no brakes. We done need brakes. We done got to show you any stinkin brakes." (Treasures of Sierra Madre." Original "Badges" changed to "brakes").

I'm just kidding you. Brakes are the most important part of a car and your counsel is wise.

As to driving a 216 with a 4:11 at 70 mph all day long, it will never happen for me. Just sounds like it is turning waaay too fast. Does too!

Best,
Charlie