The Stovebolt Site Forums The Shop Area Engine Shop 51 chevy 2 speed rear ???

Iam still in planning stages, was thinking of upgrading engines (235 to a 292) so my highway speed would be faster and the engine wouldnt be rev. to the limit at 55-60 MPH. ??? Is there a max speed that the rear end can be run at safely in high???

Why not do a gear change in the rear? Most change to a 3:70 ratio. Unless you need a new engine. I'm not sure your going to get that much more speed out of the 292. More torque for sure, but maybe not speed. Cecil...........

Unless you change the rear, or install an overdrive, the engine speed will be the same. Its probably safer (for the motor) to run a 292 fast enough to run a 6000 series truck 60 mph than it is to do so with a splash oiler, but I'd start to worry about stopping it from that speed.

I've never heard of a ratio swap for a 2-ton. Someone here swapped early hubs onto a later axle to change the ratio while keeping the early wheels, but that looked like quite a project!

And when he was done he still had 50-year-old brakes...

There are some later 10 hole wheels that are supposed to fit these trucks. I've thought about finding a set of those wheels, and then swapping the rear that goes with them under my 6400.

But my 6400 was dented by a falling tree a week ago, and I'm now wondering if it survived.

thanks for the info, I assume Iam being unrealistic with my expectations of the truck, using it to go 45 miles away 7 miles down a 7-10% grade to pick up 9000 lbs of retaining wall block and come home. Or to load and dump 3yards of dirt/clay within a 15 mile radius of home with any speed and marginal safety with the brakes on the truck even if I upgrade res. and add power brakes, didnt think the drum brakes were that week on this old truck, give what Ive seen the local farmers carry with them, or are they just being unsafe since thier excempt from so many road rules while farming.

Well first, am I correct in assuming it is a 6000 series truck?

If so, its GVW should be 16,000 pounds, and provided the truck with bed and dump wieghs less than 7,000 it should carry 9,000 or a little more.

From a performance standpoint returning loaded up that grade you mention might be a long slow haul. Even with a 292 you don't have a whole lot of power to pull that grade, and doing so at speed will require getting the gearing just right.

I'm not the die-hard inline fan some of the others here are. I believe there is no substitute for cubic inches, running it up a 10% grade loaded to the max at even 45 mph is going to require more than a 292.

But given that grade you'll be dealing with, I think I'd swap later axles under both ends just to get the modern brakes. And gearing.

Search the posts by grigg. He has put some big modern axles under a 1-ton pickup, resulting in a pretty capable looking truck. He is currently looking to build a Diesel powered 2-ton.

I don't know what you've seen loaded on one of these trucks. My 6400 has a 12 foot bed, and even with extensions on the sides it would be hard to get 10,000 pounds of most crops on it. Maybe grain, but without a much larger bed and tall sides it seems difficult to imagine. Back when I drove truck out of the field, trucks in this class didn't often carry more than eight or nine thousand pounds.

If you put two pallets of retaining wall blocks on, you got an eight thousand pound load. Been there, done that. I'm running the original (style) brakes at the wheels. Meaning, I rebuilt the factory brake system at each drum. Hydraulically, I upgraded to a dual res. and a booster. The shoes and drums are massive on these trucks, it's getting them to work properly is the trick. Now I can lock up the brakes with a 3-4 ton load of gravel on. I'm confident that I have adequate braking and I agree with Steve, no replacement for displacement. This same truck has a 350 in it. My original truck won't pull up my driveway grade in third gear, empty, where as my V-8 truck does it with a 3 1/2 ton load pushing an eight foot plow and I need to use the brakes when I get to the end. If you're going to upgrade, UP grade,
Scott

Yes its a 6400, w/at least a 12 ft bed and have seen this truck loaded with grain it had 4 ft side racks all around not sure how many pounds that would be, I have seen a 6400 with flat bed and 500 gollon tank on the back full of water not sure what that ways either but I now from the military days the water buffalo truck was the hardest to tow heavy!!! you guys are great and Iam greatfull for the info!!! Dale

500 gallons at 8 pounds per gallon would be 4,000 pounds, well within what I'd expect to be reasonable on a 6400, provided that tank didn't weigh any more than another 4000 pounds...

Its been 25 years since I worked on a farm, so I don't remember all the details, like length of the beds, and height of the side boards, so I could be fuzzy on some details, but I'm pretty sure loads bigger than 16,000 would have been real rare on trucks the same class as your 6400.

I don't think you can run 60 at a moderate RPM with a 2 speed. All two speed rears I know of are slow and slower as the two gear choices.
I suppose you could have an overdrive transmission or two, or some really realy tall tires but lack of power will probably keep you under 60 most of the time, and all of the time with a good load. Mechanicly the rear would be fine at higher speeds, if you could get it there. And with brakes in good condition should even be somewhat safe if you use common sense.

on the power thing, I'll give you an example. My 1 ton has 4.56 gears (Faster than anything in a two speed rear) and I can haul 4,000 pounds just fine in the back if it's not to hot outside, and I may get up to 50 if I am lucky. That's with a 235. But for some reason if I pull a 18' flat traler empty I can barley get out of third gear on level ground.

Again, There is no substute for cubic inches, Except a supercharger of course,.... think Detroit Diesel here...

Any way you look at it, a 235 or a 292 and a loaded 2 ton truck are not going to go fast..

The link below shows my axle swap stuff, and some of my soon to be diesel swap.

Interesting. My 1/2-ton Suburban with a GMC 270 runs great empty, but gets doggy with an empty 18' trailer behind it. Loaded its really slow. I figured it was my 3.08 gears but maybe not...

I usually pull the trailer with a 454 and 4.11 gears. Easier on everything but the fuel budget.

It does not really make sense does it?
Perhaps the resistance of having 4 more tires on the ground is much worse than we think it is?
I could cary the weight of two empty tralers in the bed of the truck, and still use 4th gear. But I can't drag one and use 4th?

I know that going to wider tires lowers your gas mileage, so maybe having four more tires worth of rubber on the ground does create a lot more resistance.

On my big truck the impact pulling a trailer has on fuel consumption seems to be the same loaded or empty.

I spend all my time towing cars /trucks, we have a 97 chevy 3500HD 2wd and you have to hook up to a 3/4 ton or better to feel the diff. in any major way, fuel economy wise the trucks diesel and gets 10 mpg empty or towing. climbing the grade I mentioned earlier is about the same you loose 5 mph tops coming up. Same when towing with my HEMTT in the army you had to be towing a 2500 golloan fuel truck to notice any major diff. Now tow a jeep trialer behind a jeep and you kno the diff.

What are you doing that has you towing cars/trucks all the time?

My primary tow rig is a '89 K3500 with a 454, and it won't beat 10 mpg empty! But given the higher cost of Diesel I don't feel real bad getting less milage and most days I'd rather hear that V-8 rumble rather than smell Diesel.

I'm not sure its completely rational, but I prefer the gas motors for my trucks.

My '62 C-30,when stock,averaged 10 mpg loaded or empty at anything under 50 mph,and dropped to ave. 7.8 mpg at 65 or more mph. After the 5.14 gears were swapped for 4.10's my mileage improved by about 2 mpg across the board.The mileage didn't change at all when I pulled the deceased 283 and installed a 350,or when I pulled the 350 and installed a freshly built 355. (Still haven't figured that out...)I'm thinking the gearing is pretty much deciding my fuel economy numbers. I'm swapping my Holley 600 four pot for a Q-jet that's been re-bushed and worked over by the owner of Custom Tuning here in Elko. He indicates that'll be good for at least 3 mpg without any other work,and swapping to a 3.73 rear will help even more.If I had a couple more 17.5" wheels,I'd go back to them on the front;they stand the same height as my current 235/85-16's,but are a narrower tire,thus,less rolling resistance. Anybody want to trade two very good 8X17.5 radials on duallie wheels straight across for a pair of 1-1/2 year old 235/85R-16's on new duallie wheels?
Speed

I towed in the military and now manage / primary operator of a small tow company at a body shop tow 5 days a week and nights and weekends two weeks a month/ along the lines of your trailer towing I have towed the bosses 22 ft crownline boat on a tandom axle trailer w/trailer brakes and its really tuff to tow. My driving style has the mechanicle brakes applying have the time cuase if Iam not accelling Iam deccelling and the brakes try to apply so if you have mechanicle brakes and the truck slows significantly between shifts it really create drag

I have a trailer with surge brakes. I hate it. I like the brake controller approach much better.

I pull a 16-foot flatbed trailer with my 66 C-10 and get about 8 mpg. It has the original 250, 3-speed tranny and a 3.73 posi. I notice the trailer empty in all 3 gears and especially going uphill. Empty it gets between 11 and 13 mpg. My grandpaw pulls the same trailer with his 71 C-10 with the same drive train, but he has the truck loaded to the max and has a John Deere 750 with some kind of emplement and we have to us second to get up most hill in my area. Mileagewise, he never checked it. But stopping is a different story since his has the original brake system, mine has a rebuilt original style hydraulic system and neither of us have trailer brake controlers. My dad drove a rig for a local grocery store chain and he said that there is a big difference when the number of tires on the road is increased.

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66 Chevy C-10 restoration project/work truck