The Stovebolt Site Forums The Shop Area Driveline Woah! She’s slow.

My 9 year project hit a major milestone today. I got her out on the open road for the first time.
1958 Apache 235/3 speed, stock wheels and tires.
At 45 mph she was screaming loud. I still had pedal left, but it sounded like it was winding out fairly high. I don’t have a tach, so not sure exactly how high.

I’ve seen threads about these trucks being slow, and I think it’s going to end up with getting a different rear end. I built the truck to be stock, but st 40-45 mph I’m worried about getting rear ended!

Anyone have some wisdom to share?

I’ve got a 49 3/4 ton. It had a 5.14 gear in it. There were three ratios sold for these rearends. I swapped the pumpkin for a 4.10 and gained 6-7 mph. But I don’t know what you have in a 58. If it’s an Eaton HO52. It’s an easy swap. That axle was used from 47 to 1972.

Don

What series is your truck? Just saying "Apache" doesn't tell us much...it could be a 1/2, 3/4 or 1 ton.

Mike B

Sorry, it’s a 1/2 ton swb fleetside

Yep, they sound like that. Screamin!!! Probably has a 3:90 gear in the rearend, get a tach and see what it says it's . You should be able to go 55/60 without any difficulty. These old trucks are not like the new ones quiet and comfortable. You drive these not ride in them.

Yeah sounds like the darn pushrods are going to launch out of the hood!

....and the faster you get your rig going, the better the brakes need to be. I swapped the 4.11's in my rig for some 3.55's. " Good move" says my truck. Yes for a tach. 60mph at 2500 rpm.

Are the valves adjusted properly? That has a big influence on how it sounds.

Just for grins, take the fan off and make a highway-speed cruise for a few miles. You don't need a fan above 30 MPH, and I'll wager the engine won't sound half as stressed once the fan noise is out of the picture. Any engine speed below 2500-3000 RPM isn't going to hurt a good-condition 235, even if it is a little noisy.
Jerry

The valves are good I checked them already. I just noticed that the pinion seal is leaking. I think the decision has been made.

Does anyone have suggestions on a good axle upgrade?

I am not the best person to advise anyone just ask around but in my 54 1/2 ton, I have a 1979 Nova rear end with 2.73 gears and an s10 5 speed. But I live in Indiana and it is usually flat and it works for me. I have been down through the Smokeys and on the interstate, it does fine but on back roads, it takes a little shifting. Best of luck.

With a 3 on the tree, I would be looking for a 3.73 out of a '67-'70 half ton truck. Its a 12 bolt rear end. You will have to weld on some spring perches.
Any ratio numerically less in number (like say, a 3.55) would be a sluggish in first gear under any kind of an incline.
Carl

Another option would be to swap the transmission for an overdrive unit instead of swapping the rear axle. The SM319 was an option on these trucks from the factory, so they are a direct bolt in, even using one from a Tri-5 passenger car. I have one in mine, and 70+ is no problem for the 235.

When the question of top speed comes up, I always ask myself about braking.

I had a serious case of drum-brake fade in our '65 Chev on I-80 in Wyoming one time (~1969) when a big buck deer, trying to block most of the 2 lanes, stared me down. I couldn't stop but thankfully I could steer a bit. Drifted right by him.

45 MPH is great for me.

I’m not familiar with the sm 319. Does it shift the same as a 3 speed? How do you shift it to overdrive? Do you know if a driveshaft mod is required? Thank you for the help!

I thought the same on my first drive in my 37,that problem has been solved with a T-5 and 3.55 gears.

The SM 319 is a variant of the SM 318 3 speed that is standard in the '55-'66 trucks. Both transmissions also saw use in GM passenger cars in the same time period. The SM 319 is setup with a Borg-Warner overdrive unit in place of the tailshaft and its housing.
The main part of the transmission is the same as the standard 3 speed, so the shifter hookup and operation is identical. The overdrive is, if installed as the factory did it, shifted electrically via a solenoid on the housing. The shifting is done automatically by lifting off the throttle at approximately 28 mph (that speed can vary depending on rear ratio and tire size), which is when the contacts in the governor close. Overdrive can be used in any forward gear. There is also a manual lockout cable which locks the overdrive, making the transmission operate as a normal 3 speed.
If you use a transmission from a '55/56/57 Chevrolet Passenger car or '55-'59 Truck, no driveshaft mods will be required. The only change, depending on what the trans came from, would be to swap the shift cover out as Passenger and '55 6 cylinder Truck versions are different from '55-'59 Truck.
Here's the shop manual section from the '55 manual can explain things a little better on operation http://chevy.oldcarmanualproject.com/shop/1955truck2/55ctsm0715.htm
I've had one in mine for the last 20 years, it's probably the best thing I did to it.

40 - 45 mph in my truck with standard (1956) 3.9 rear is about 1800 rpm . A standard 235 1/2 ton should cruise easy at 60mph , it will go faster , but your mileage will go away

If you have too much noise , determine where it is coming from and fix that . I predict it may be a cheaper option .

Jerrys "pull the fan off" is a good way to isolate noise issues.

Consider taller tyres as a small gearing adjustment .

I agree with the brake comments .

Great info guys I really appreciate it. Love the idea of the sm319. I’ll look into finding one. I did the brakes with a hidden booster and discs on the front so she stops great. Not that I want to go that fast, I just want to go with the flow of traffic.

Took my truck out for a spin yesterday. With 3.55 gears in back behind a SM420, my RPM's are 2200 at 55 MPH, 2600 at 60 MPH.

You can get a 3.38 gear for the '55-'59 (and up through '64?) half ton rear end, but I'd suspect you'd be feeling slow from starts with that versus slow up top with what you've got. I'd be willing to bet, based on my experience with my '50 half ton 3spd/4.11 and 216, that you aren't actually pulling as many rpms as it sounds like it is at speed.

'63 is a different axle.
3.90:1 was stock.
I know you can cruise 65mph all day with a 235 & 3.90 rear axle because I drove To MA & back to OR several years ago. with no issues. Changed oil on the east coast before heading back. Still running same engine now, doesn't use oil. If it's in decent condition & valves are adjusted will not be an issue. Used to run 80 MPH with it back in high school (1970s) road racing a buddy with a Jeep wagoner hurricane 6.

I replaced the Eaton HO52 rear end in my 49' 3600 with a Dana 60 from a 69' F250. Almost exact same width backing plate to backing plate. I had the drive shaft shortened by about 2.5 inches and a yoke welded on to mate up to the Dana 60. It has a 3.73 ratio along with 29" diameter tires and I can hit 60MPH at 2500 RPM with the stock 4 speed transmission.

Skidmarks rig is a 1/2 ton

Axle ratio, tire diameter, and engine RPM are useful for comparison regardless of truck model.

Back in the mid-1960's I ran a 58 Chevy 2 door sedan with a 235, 3 speed, and a 3.70 rear end. It had low profile 14" tires on it, standard for that model. I had no trouble keeping up with traffic at 65-70 MPH, and the mid-80's were not too difficult. With 3.90 gears and the same 1:1 high gear ratio in the transmission, a bone-stock pickup with a 235 should be able to do similar speeds because of the taller tires.
Jerry

Today, I stuck the GPS onto the windshield and took the truck out on the highway. At 90 KPH (about 55 MPH), the speedometer indicated 40 MPH; this speedometer error is pretty close to what I calculated it would be. Engine RPM is about 1750 at this speed in 4th gear.

Rear axle ratio is 2.41. Tires are 767 revs/mile.

So I was looking into a different differential. Will a new ring gear and pinion work? Are these old rear ends compatible with a new ring gear swap or am I wasting my energy?

"1958 Apache 235/3 speed . . .
Will a new ring gear and pinion work?"

As EBS posted above

If you go that way, you might want to also use this installation kit.

You can get the install kit MUCH cheaper at Jeg's.