`63 Chevy Sidestep/does`nt run down the road very fast

cadillac

#1

I have a ~63 Chevy Sidestep pickup.The body has been restored to museum quality.The engine and trans were redone 20,000 miles ago.My problem…when going down the road,top speed is only 45-50 mph.What needs replaced mechanically ie…steering arms? I`m a novice so be kind!


#2

Will the engine rev when in neutral? Will the truck coast if shifted to neutral at 45 mph? Is this an automatic? If so is it shifting out of LOW range? You might get a basic repair manual and go down the list of possible causes.


#3

Most body men when asked to do a “museum quality” restortation also install a device that prevents the vehicle from being operated at any thing above “museum transfer speed”, is yours still turned on?


#4

One simple thing to check is to make certain that the accelerator linkage is adjusted correctly. Remove the air cleaner, hold the choke open and look down at the throttle plates. When the accelerator is wide open, the throttle plates should be vertical (90 degrees).


#5

It does rev in neutral.It`s a 4 speed.Thanks for your advice!


#6

Thanks I will check this.


#7

Oldschool is pulling your leg. There is no such device. The body man who did the work will get a good laugh out of it, at your expense, if you ask him.

The accelerator linkage is a good guess. Also check the points setting and ignition timing in that sequence.

Does it run smoothly at 45, or miss out and sputter? If it’s sputtering, suspect the fuel filter and then the fuel pump. Check those after the points and timing are verified.


#8

Is this a half ton, 3/4 ton or 1 ton pickup truck (C-10, C-20 or C-30)? If this is a C-30 (one ton) with a 6 cylinder engine, it isn’t going to traverse the highways at breakneck speeds, although I would think it could do better than 50 mph. I had a 1950 1 ton which was a 6 cylinder and its top speed was probably 50-55 mph.

I do know that some trucks had governors. The U-Haul trucks I used to move years ago had governors that limited the top speed to 55 mph. It would be unusual in a pickup, but it might have been fitted with a governor. I also heard about a situation where the rotor in the distributor had a crack in a certain spot and when the centrifugal advance weights would advance to this spot, the spark would jump from the rotor to the weights and effectively act like a governor. This was in the monthly series “Tales from the Model Garage” and the proprietor, Gus Wilson tracked down the problem where other mechanics had failed. Far out, but I suppose a possibility. Distributor rotors are a cheap, easy repair.


#9

I knew there was`nt such a button…Thanks for your other suggestions


#10

Look at your front tires. If they are wearing out on the inside edge, you need an alignment and probably tie rod ends, idler arm or ball joints.

Make sure the vacuum advance moves the breaker plate. Sometimes it will hold vacuum but it is stuck. Check for broken vacuum lines, they usually split at the ends.

Then there are old plug wires.

Stepside may be a better name. I don’t know about sidestep, but it might have been and I just missed it. History happened so long ago.


#11

I think you would know it, but is the clutch slipping? If so, the engine could be running just fine, but the slipping clutch prevents you from going over 50 mph. One quick test–set the brake, put the truck in gear and accelerate as you release the clutch. If the engine stalls right away, your clutch is o.k. If it doesn’t stall, your clutch is slipping (assuming the brake is not allowing the vehicle to move).


#12

of course it`s stepside.thanks for your suggestions anyway.


#13

If the point dwell is too low or the spark advance is not operating power will fade drastically as speed increases. A restricted exhaust will also put an anchor on the truck.Do you have a timing light? How about a vacuum gauge?


#14

Yes to both.The restricted exhaust is a good point.Thanks


#15

Just curious- did the truck always run slow like this, or has it just started doing it? Do you have a tachometer? What RPM is the engine turning at the top speed it’ll go? Do you know what the rear gear ratio is? I’m guessing perhaps there is no problem with the engine, but instead it may originally have been a six cylinder with a steep rear gear, and you’re running out of engine before you get to the speeds you want. Vehicles can have a lot of changes made to them in 47 years; a previous owner may have put in a much steeper gear to suit whatever use he had for the truck.


#16

No tach now.I`ll have a mech check it out.Thanks for the help.


#17

Diamond Chevy’s post just rang a bell with me. If the transmission has been replaced the speedometer gear could be totally miss-matched for the final drive ratio. Could the truck’s actual speed be 75 when the speedometer is registering only 50?


#18

When you are doing 75 mph in one of these trucks the least significant indication of this speed is the speedometer.


#19

The trans has been replaced.However,Im positive Ive never been able to get above 50mph.Thanks for your info.


#20

Check the vacuum advance if it has one? Also in the distributor if I recall there may be plates that need to slide to provide a centrifugal advance, possibly vacuum advance or centrifugal advance is not working.