The Stovebolt Site Forums The Parking Lot '60-'66 Trucks Higher Gear Ratio/mileage improvement

Now that I'm retired and building my confidence in regaining my mechanical abilities from my youth, I'm studying on doing something to get better mileage with my 63 C-10 as it is my preferred mode of transportation. I have been advised by several that the best, easiest thing to do is too obtain an automatic van from the 70's and just swap it out. To my way of thinking this sounds to good to be true, and you know what is said about that. An advice, suggestions on where to find information, or warnings would be appreciated. I have seen this topic covered on the earlier modles, not the 60's truck, in particular, the step child-redheaded 1963.

I'm not sure why someone recommended that particular combination for better mileage. In my experience the mid 70's vehicles were a mixture of somewhat larger engines (350's), lower compression, and an attempt to satisfy newly imposed smog requirements. None of this led to better mileage. The best way to obtain better mileage is to install an overdrive transmission of some type, 700R4/2004R automatics, original 3 speed overdrives or the later T5's. There are also rear end options. Of course engine condition and tune up are always important. These trucks are heavy and push a lot of wind so they will never be truly economical.
Fred

I have the same question as 63 C-10 Carolina Fleetside, except the vehicle is my son's '66 C-10. What third members fit these trucks that have more highway friendly gear ratios? His present combination is a 355 sbc & TH 350 trans with the original '66 rear end.

Thanks guys.

The '63-'76 C 10s used the Truck version 12 bolt. Aftermarket gears are readily available from many vendors, Randy's Ring and Pinion seems to be one of the better ones on price. Just about any ratio you could want is available, from the 2.90 all the way up to a 5.88 (not suggested, 1/8 mile drag race gear). Yoyu may have to change the carrier depending on what gear you want to run. Side note, '63 and '64 truck 12 bolts use 17 spline side gears, those are not available aftermarket. If you need to change them, or want a limited slip, you will have to change the axle shafts to the later 30 spline.

Fred, thanks for the suggestion. I guess I need to clarify. I have a very original truck with factory build sheet from dealer, option sheet and original bill of sale. I really don't want to cut it up, which I think I would have to do if I changed the tranny out? I wanted to go the "If I ever need too, I can put it back stock " route. Bill, I am finding more everyday that is unique to the '63. Thanks gus for the comments. Perhaps I need to leave it as is, and limit my driving to the cruize ins. It drinks more gas than Dean Martin did booze!

Longbox, do you know what OEM ratios were used? Are some more common than others or unique to particular years? It would be nice to find a factory setup that my son could use in his '66 C-10.

I am just now finishing a 4.11 to 3.55 conversion in my '36 Chevy pickup. That has been quite an exercise using a '37 Chevy car rear end modified to fit and OEM gears from a '51 Chevy car. I'm really curious to know if the ancient 207 cid engine will be able to pull the new gears. There are some steep hills in my neighborhood.

Original trucks are great but sometimes not practical. Changing the rear gears is probably the least noticable but whatever you choose would not match the build sheet. I make changes to my vehicles based on practicality, safety, and my personal preferences. 3 speed OD's were available for 63's but would require a driveshaft modification. I guarantee you it would be more driveable and get better mileage.
Fred

On my '60 I changed the rear gears and picked up 3-5 MPG with a drop of 400 in the RPM. I had the stock DANA 44 and changed from 3.92 down to 3.23. I would have went lower, but I have a 305 V-6 as my mill and that was a good fit. Everything you need is at Precision Gear. Look for the yellow ring and pinion set section.

http://www.precisiongear.com/

When you are doing this switch, get the installation kit that they recommend. It will let you change out all the barings and give you all the shims and spacers you'll need. Put in new wheel barings and run a scourge or demin wad through the tubes to clean them out while everything is open. You'd be surprised just how much rust and debris will come out,while you're at it and everything is apart.

Here are my pictures for the one we did.

http://rides.webshots.com/album/570438270cjSEvE

Hope it helps clear up some questions.

My '62 gets 17mpg with a 3.23 Dana rear end, tall tires, 4spd OD manual trans from a '81-'87 Chevy, 290hp crate 350, old Edelbrock C3B intake and 600cfm 4bbl carb.

The overdrive is .72:1. I would get a lot better mileage if I didn't honk down the highway at 80-85mph, but I can't help myself. Normal cruising speed is 75, in the left lane. I drive it like I would any other vehicle.

My 2001 Dakota got the same mileage, driven the same way.

I think a more modern intake, more free-flowing exhaust manifolds (2.5 inch Rams Horns in place of the small 2-inch on it now), and some other improvements would bump that up a bit.

I also have a clutch fan on it, which helps.

I'm also certain either a 2bbl carb or a Quadrajet would help things too... though really, keeping my foot out of it would be a the first huge step!

-Brad

3.07, 3.73, and 4.11 are the listed options for the '66 1/2 ton. Just judging from the codes, seems that 3.73 is the most common, it has the most code listings, with 4.11 beinbg second. 3.07 only has 1 listing.

How many miles do you really put on your truck? If you take the money you will spend on new rear gears, or a T5 swap, or whatever, and then calculate how much fuel you could buy with that money you might find that leaving things as they are might just be the best route.

That being said I can never leave things well enough alone on my truck. Here is a link to an excellent gear ratio chart that you might find helpful.

Good luck

http://www.sierrabronco.com/TireGearRatio.htm

The other thing to consider, besides fuel costs, is engine life and the quality of life while in the truck.
We're used to our daily drivers having OD, which means we're used to lower engine RPM. You'd be surprised how much difference 20-percent more rpm makes while trying to carry on a conversation.
It's also hard on the engine. Why zing it down the highway at 3,000rpm, when different rear gears and an overdrive can put it at 1,700rpm?

-Brad

For what it's worth, I just converted my '36 Chevy pickup from 4.11 to 3.55 gears. It was a big project because the 3.55 gears from a '50-'54 Chevy car required use of a '37 Chevy car rear end but it's well worth it for the 15 % drop in RPM creating a much quieter cab where we can have a converstaion without shouting. The little 207 cubic inch engine still pulls a long 11% grade near my house easily in second gear no sweat.

Brad54 hit the nail right on the head. Sometimes it's more about the quality of life than MPG. My '66 C10 has a built 350, turbo 350 and '72 1/2 ton rearend with 373 gears. I'm at the point where I can't tolerate the low rearend anymore. By the time you get where you're going your exhausted and you know the high RPMs aren't doing your engine any good. I bought a good rearend out of a '72 Suburban with 308 gears for $50 and spent another $75 to get it ready to put in the '66. Dollar wise this makes more sense than an overdrive or changing gears. I've owned several '71 and '72 1/2 ton pickups over the years with 350/350 and 308s. From my experience that's a really good all around drivetrain combo.

I'm thinking of putting an overdrive unit behind the trans there is a old company that I dont think is around anymore called hone-o-drive that made a devorce mounted over drive that where used on motion super cars and other cars in the late sixty's and later on mobel homes. The thing I like is that they dont boilt onto your trans.
Bob
About the drive and it's creator Fread Hone
http://www.stangerssite.com/honeodrive.html

Google search honeodrive
http://www.google.com/search?source...f&aqi=&aql=&oq=&gs_rfai=

A overdrive transmission would have been easier, you would have maintained the performance of the vehicle with the 3:73 rears and still have lowered your rpms while cruising down the interstate.

I have a similar deal.. My 64 has a 4:11 and it is hard on the wallet to drive. I plan to just rebuild a rear end with the highest gear I can find. I do not ever plan to pull anything with my old truck so it should not matter very much.

On a side note, I have seen where you can put a set of 3:73 in a 4 series carrier, and also in a 3 series carrier. I am thinking of putting in a set of 3:23 or what ever is around there into our 66 Burb which is a 12 bolt truck with 4:10 in it. If I find a rear end with 3:73 gears in it, how can I tell wether it is a 4 series or 3 series carrier? I would be looking for a 3 series.