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I'm trying to figure out what it'll cost to drive the new/old '57 GMC dump truck I got home next time I come to Reno. It's a 1957 GMC 350 dump truck with a 270 six,SM420 4 speed,and 2 speed axle,and 22.5 wheels.
Can anybody with a similar set up give me some idea what mileage it might get? I don't run more than 60 mph,and don't plan any stops other than gas and coffee.
Thanks for any info you choose to share!
Speed

My 64 two ton GMC with a more modern 350 SB Chevy an SM420 and a two speed rear gets about 6 MPG and she is screaming at 55. I don't know for sure but chances are it gets better mileage with the 350 than it did with the stock 292. The SB is a little happier at the higher RPM than the original six. Oh and it seems too get about the same empty or loaded.

Oh and yes it gets worse mileage than my old 8 axle KW dump truck at 105,500 pounds with a 550 CAT and an 18 speed. I load the GMC to 26,000 GVW and 31,380 CGVW with the 12 ton equipment trailer and 17,000 pound 307 cat excavator behind it. Dragging 23,000 pounds of trailer and machine is a slow go drops MPG to about 4 and I am sure it is shorting the life of the transmission.

Knowing your rear gears and total weight would help in guessing this right, but I'd bet 6 mpg is optimistic and running 60 mph impossible.

Your gearing was chosen to get a very heavy load moving, not to move an empty truck fast.

I don't recall how hilly the drive form Reno to Elko is. I'm thinking you will be going down in elevation, but if you are climbing much, that will be slow going too.

300 miles? At 5 mpg you'll burn 60 gallons. If it only has a stock tank you'll be stopping a few times for fuel and coffee...

Anyone know what a 261 in a 2 ton truck gets? Ballpark... Just wondering what it will cost me to drive it on a 200 mile round trip. Thanks.

If you have to ask....

Yea with gas as high as it is, I guess I already knew the answer. :-)

Bring a high limit credit card, gas cans and a cell phone and enjoy the trip. Fuel economy is a mute point in the old truck world. If it ain't burning it, it's leaking it (or is that the oil?),
Scott

Milage? You're kidding right? I'd guess somewhere in the range of an M1 Abrahms tank! :p

If it were me,...
I'd say get a 55 gallon drum with a hand-op fuel pump, strap it in the fwd. left corner of the bed. Top off the truck and the drum, grab a thermos of coffee, & have a nice trip.

I did some number crunching on my nifty gear ratio calculator for my beastie once, gave me a blazin top speed of 53MPH in my '56 370 dump. That was being conservative since I didn't have exact numbers tho.

BTW, if any of you folks wanna give me the diameter of the tire, the gear ratio/s for your rear end, the ratio for your highest gear (or all of them if ya have em), and the RPM limit of the engine, I can get you the exact speed limitations for your rig.

I guess you're right about the mileage. I'm just gonna take all the money I can pull together and stop at every town on the way for gas.
Hevyhauler;
You're probably right about 60 mph. No big deal,I'll just set the road speed at whatever makes the engine happy.
I plan to take my '45 Mack for a short test run on the highway (30 miles or so) to see how it's gonna handle the trip. I just talked to a friend up in Elko who offered to bring his tractor trailer down and haul my trucks back for me,so if the Mack passes the road test I'll go ahead and drive it back towing the '62 one ton,but if it fails(not enough power to maintain high gear,too roadwild,etc.)I'll just have the Mack and the GMC hauled and drive my one ton.
OldSub;
The drive from Reno to Elko's mostly relatively flat ground with a total climb from about 3,500 ft. to 5,100 ft. and 3 passes to go over. Nothing really extreme.
BTW-we got the boom finished today,I tested it by swinging it out to the right and picking the rear of Dutch's Ford Ranger up off the ground a couple of feet. (He wasn't very amused...)I'm sure it'll be strong enough.
Speed

do you have any pictures of the boom on the mack

Come on guys...... It's NOt miles-per-gallon..... With old trucks... (especially BIG trucks)... You need to remember one thing.... Gallons-per mile..
Michael

Really...what does a 2 ton with a 261 get for MPG?

No, no, no... Its SMILES per mile!

I used to drive a 60 school bus that was rated at 2 tons. Had 4speed trans, single speed rear axle. It would run 60 empty fairly easily, but only got about 6 mpg on the road. It had the 261 6.

Thanks!!!

Sounds like a school buss rear axle may have the gears that some of the guys are looking for.

It would run down the road fairly easily at 60. Still had a good bit of power to climb hills. This was in a 1960 Viking chasis with a 48 pass Wayne coach on it. Had the old split rims on it. Always hated working on those.

I've had it to 45 MPH but it had bad brakes then. I'll give it a try once I get it all back together again with the new brakes... I'll let you know.