The Stovebolt Site Forums The Parking Lot Tons 'o Fun Highway speed

Friend of mine is doing a 58 Chevy 1 ton and is wondering how to get 60/65 mph. 235/4 speed, rear end ratio unknown. What have some of you guys done to keep up with traffic?

Weeds

If you're not going to change the engine for a faster running one or the transmission to one with an OD then the only variables you have left are tire size, auxiliary transmission, and rear axle gear ratio.

Run the numbers here
http://www.onlineconversion.com/bigger_tires.htm

One method would be a center section from a 60-72 truck with the GM/Eaton axle. They typically have the 4.11 gear, you may luck out and find a 3.90.

Another option is a complete rearend swap. I don't know if the truck in question is a dually or single wheel, or even if axle width is an issue, but here it goes. GM has a full float 63" WMS-WMS (wheel mounting surface) and a 67" 14 bolt rearend. The good thing about them is that they are fairly common and they were made from 72 to present day, with only minor changes and a pretty good selection of gear ratios. Rearends from Dodge and Ford vans seem to be another popular swap. The Dana in the Ford is kind of hard to come by. They mostly were built with the Sterling axle, which is still a possibilty. You'll want to look for a full float Dana axle in the Dodge vans otherwise it'll probably be the Dodge semi float 9.25 rear.

At some point, you're going to run out of HP, w/ a high rear gear or load, then you can look for a 261(looks same as 235,) 292(modern looking,) or GMC 302(move radiator to front of core support) to maintain your choice of higher road speed.

A little clarification; The third member you would want is from a '68-'72 C20, generally with a 350 and automatic transmission. All others will be either a 4.56 or 5.13. The 3.90 mentioned is not an oem gear, they were a low production aftermarket run that seem to be impossible to find. The company that had them made seems to no longer be in business, though their website is still up.

When I came to the realization that my 1941 1 Ton Long Bed pickup was not going to move over 45 mph without some changes and the fact that parts to get me up to speed were going to be hard to find/duplicate I replaced the whole drive/running gear assembly.

I started with a narrowed modern 3.73 rear end with wider rear brakes, single drive line instead of 2 piece, a 700R4 transmission (.70)overdrive and a small block stock 350, a radiator to match engine size and cool transmission and finally disc brakes on the front. If you want to cruise fast you need to be able to stop fast.

End result is 70mph at 2000 rpm. I got tired of chasing hard to find parts trying to make the truck do what GMC did not engineer it to do.

My 49 1 ton would do 40 tops and sounded like the engine was going to fly out straight out of the hood. I bought a 3rd member from a 71 3/4 ton w/ auto and it has a 4.10 rear end. They are hard to find, and harder unless you know it is/was originally a 3/4 ton w/ and automatic. otherwise, you have to crack into it and count teeth.

Excited to get it back out on the road and see what switching from the 5.14 to the 4.10 will do. Everyone says it doesn't affect the low end too badly but improves the higher gears. Mine spent a good life working. In retirement, she's just gonna cruise to farmers markets and parades. Maybe the lumberyard on a fine sunny Saturday.

Actually you don't have to open it up to determine what the ratio is. All you have to do is make sure that only one wheel end will turn, and then count how many turns of the yoke equals one turn the wheel. If it's just a little over four turns that would make it a 4.10 to 1 ratio. 4 1/2 turns would make it a 4.56 to 1 ratio etc.

I've been told by a knowledgeable person that there was indeed a factory 3.90 gearset, used only in some big block 3/4-ton pickups in the 1969-71 era. He's the only person I've ever talked to who has seen one.

Some manual and leaf spring applications would also have the 4.10, but the auto/coil combo is the most common.

No need to count gear teeth, either use the method outline above this post or look for the markings on the edge of the ring gear.

GM says different. Cross referencing the available ID guides to the GM Heritage site, there's no listing for a 3.90 in any 3/4 ton. The factory big block truck did have an option for a 3.54 gear, but those were Spicer/Dana axles, not Eatons.

Well, I don't know where it came from but a fellow bolter in Mi. sent me a pumpkin that is 3.90.... .he says it came out of a 56 or 57 pickup. I do not know but I did look at the ring gears ect when I put a new pinion seal in it.

....I guess I've been told wrong but I've always "heard" there were 3.90's in a lot of the pickups and that it was the later years like the 60's that had even a higher gear???

I'm not claiming or dis-claiming anything here. Just adding to the confusion!!!

1/2 tons from '54-'62 had a 3.90 gear as standard equipment.

I would add for the "doubting thomas" that unless you have a need for a higher gearset, or the rear end is coming from a known, unmolested truck, take the rear cover off, count the teeth on the ring and pinion, just to make sure. I know I bought mine w/o opening it up, and got lucky. My advice if I were ever buying another one, I'd take the 5 minutes to pop the cover off and count the gears.

As I stated above, they should be marked on the edge of the ring gear. Or, if the transmission is out or it's in neutral, just rotate one tire and count the driveshaft revolutions.

Aggie Jon- on a 58, there is no cover to take off. You would have to pull the entire center section.

10-4.

Are you talking about an Eaton HO72/HO52?
I've never seen one that didn't have a removable rear cover.

Interesting. I've pulled several center sections from these axles clear up to '72 and pulled the rear cover off every one of them to confirm the gear ratio.

New here,
Was just looking at the talk, I have a 48 3804 9 ft., live in southern Ca. and just had the rear redone out of a 78 3500, that the shop shortened and got some new axels made to fit the wheel base. Not sure of the blah blah to 1 ratio but I can travel at freeway speeds. The 235 with dual YF carbs gets me along just great.

Had a 48 1 ton it would go along at 55 with 18" tires. The noise didn't bother me at the time. No idea what the rpm was.

If the U-joint is off, the ratios are usually stamped on the front end of the pinion shaft.

Weeds,

I used to have a 1/2 ton 51 that was restored with the conversion
kit offered by "Patricks". This rear-end kit involves the ring and pinion gear swap only I think. Patricks, nor anyone else seems to offer the same conversion for our 1 tons. I called Patrick's seeking advice. An old timer there told me the entire rear end from an 88-92 Ford 1 ton Van would bolt right up and give me the increased speed I was seeking. I found one in a junk yard for $75. He was right, It bolted right in. I'm not finished with my restoration, but will update everyone once I get it on the road.

Loadmaster235,
I'd be interested to know what gear ratio the Ford van rear has and what wheels fit it. Will the original chevy 8 hole wheels fit? Thanks.

Jeff

Will the ford van axle handle dual wheels?
My 1 ton is a dually.

The Ford Vans from the early '70s into the late '80s (I think) used mostly Dana 60s. There are lots of different brake and wheel options. The stock 1T and 3/4T "small 8" lug pattern is exactly the same as GM and Dodge of the period. The stock sizes are 16.5 X 6,7,8 and 16 X 7, 8 for the plain-jane wheels. Most were 4.11 and 4.56. The 4.11s were found behind the 300 L6 and SBFs. The 4.56s were behind both sixes and SBFs and in both 3/4 and 1T.

Around here in Central NC, the small time stock car guys sucked up every Dana 60 they could find, and the 4X4 guys aren't far behind, so those are hard to find. I hope this helps!

best Wishes,

Les

Ford is still using the Dana 60 in the E series vans, though most are now semi-float instead of full foat. They are still using the 8x6.5 bolt pattern as well. 3.55 is a very common gear on the later vans. GM and Dodge also use the same Dana 60 in their vans, not 100% sure on the widths.