Options for a truck rookie

[PJsthnam]

To start, my traveling brick is suckin' the gas right out of my wallet. It'a a DD (I need a truck for work) so she may have to go. I don't have the kind of cash to put in a newer motor, or rebuild with better internals, or trans swap, or gear vendor, etc. What I might be able to do soon is buy another cheap truck then sell the 72 to try and recoup the money. I want a full size truck (I'm 6'1) and american made. I really don't want to new of a truck. The 72 has a 350 w/ 400 tranny (3/4 ton). I know the newer (80's or 90's) trucks can get better milage, but I was wondering what kind of milage a 50's or 60's truck with a straight 6 six and manual (would prefer auto) tranny would get. Any input would be greatly appreciated. Good or bad. Thanx in advance.

[smn69]

Not a whole lot more then you are getting now. Even the 6 is going to max out at about 14 mpg in real world driving.

[junkyardjohn]

As you well know these old trucks aren't exzactly fuel mizers, no matter what you do. I had (something i aquired in a trade) a 93 full size ext. Cab 4x4 with extreamly low miles (like 30,000) & it had a 350...700r4 & 3.08 axels. I only drove it for about six months but it got about 17 mpg all the time. There should be a ton of them out there for sale right about now for not a whole lot of money. 17 mpg doesn't sound like much, but it was almost twice what i was getting in my 71. Hope this helps. John

[67chevemall]

70-80's Toyota Helix is the only way to go for DD truck

[QKENUF4U]

cant help ya with the older stuff but my 91 k1500 350/auto gets 17-20mpg at all times (160k+).... to bad your truck is a long bed or we could talk .... lol

[Fred T]

The best bang for your buck will be a differential swap. If yours is the 10 bolt it will be 4.10 or 4.56 gears. Find a 14 bolt with 3.42 gears at a junkyard. If you can weld carefully cut the brackets off your differential and weld them on the new one. Also get a measurement across the wheel mount faces. Most junkers will help you find a differential that will work.

[classic70]

I know you do not want a newer one but by buddy has a 1999 chevy 2wd with the 4.8 and he can get 22 hwy and 18 pulling his bass boat.

[oldblue1968chevy]

how exactly do you go about welding axle addles on diff. axle.

how do you get them correct? wondered this for awhile? thanks

KEEP THE TRUCK

[capev86]

swap the trans.....think how much time and money you will spend buying another truck, swapping insurance, yadda yadda. provided you have a mild engine you should be able to get far better gas mileage with better gears.

my 72 burb c-20 has a 4.57 rear gear and no overdrive. so far the mileage has been 10-11mpg. i have a 4.10 third member to swap into the HO52 rear axle and planning to pick up an OD unit for the 3 speed saginaw. figure the fuel mileage should be up around 15-16 on the highway at 60mph. my dad's all factory 84 burb 1/2 ton 2wd w/ 350, q-jet, 700-r4 with lockup and 3.73 gears got 17-18 and actually managed 19mpg on one tank of gas which is amazing considering it was worn out and burning a bit of oil. even when he swapped in the the 406sbc (going in my 72 eventually) gas mileage was consistently 16 and above.

newer vehicles benefit from improvements but the flip side is they weigh more with all their saftey features and luxury extras thrown in.....so the gas mileage is about the same when comparing apples to apples (gear ratios, engine size, etc). i'd say find a 200-4r cheap and throw it in there if you have a turbo 350 auto......it is nearly a bolt in. also use a lockup torque converter.....that will also help reduce excess rpms when cruising. the 3/4 ton trucks have taller tires which helps marginally (a 3.90 in a 3/4 ton is like a 3.73 in a 1/2 ton). unless you have a diesel, a 4.10 is a good choice in a 3/4 or 1 ton like a 3.73 is the best in a 1/2 ton provided you have an overdrive for the other end of the spectrum.

[PJsthnam]

I've already changed the diff. from 4.10 to 3.54, so I think an OD tranny would be too much. It now has the stock 400 tranny(3/4 ton). I would have liked to try the Gearvendor, But holy crap, The're almost as much as I paid fo the truck.

Did somebody say Toyota???:dohh

[capev86]

no, a 3.54 gear will be good with an overdrive, since it is only a little softer than 3.73. the 3.08 with OD is better than without, bu really no better on gas than the 3.73 and OD 'cause you still have to push a lot of air and move a lot of weight.

3.08 x .7 = 2.16
3.54 x .7 = 2.48
3.73 x .7 = 2.61
4.10 x .7 = 2.87
4.56 x .7 = 3.19

as you can see, the 3.08 is very soft for a truck. if you have an overdrive, it isn't much better than the 3.73. even a 4.10 with OD is better on the highway than a straight 3.08 gear. if you have a 3.08 rear and live anywhere with hills (or tow), it is a good idea to get a more aggressive gear in the back AND add an OD trans. when you get the overall ratio comfortably under 3.00 you start saving gas provided you don't drive 90mph.

[capev86]

swap that turbo 400 for a good 700-r4 or 200-4r. you can build them up to take anything the 400 can take......cheaper than the standalone gear vendors and a cleaner install.