The Stovebolt Site Forums The Shop Area Engine Shop Changing the running gear

Ok, I have a 54 3800 panel and I drive it all the time but, the miss thinks it's to slow and to hot to go anywhere more than 30 min. away.(No, thats not the reason for not showing up at Belton on the Fourth but, the fifth} So yesterday I went to the wrecking yards in search of a rear end and no luck. A friend of mine suggest that I change all the front end and rear end to 1/2 ton(get rid of the 8 lug wheels). I can find all types of rear ends with five and six lugs at those places. Somebody help this old man make a decision here, keep the panel like it is or change the running gear, front and rear. Now I can't get rid of the wife . So whats left?

Thanks, Tony :confused:

If you dont work the truck and it has a open driveshaft put in one of the 4 speed o/d trans from a 80s truck,it will make the trips a little faster. I know what you mean about being slow as I have the same problem with a 37 1/2 ton. I plan on changing the trans and rearend to be able to go faster. Jeff

Tony - the 3800 is actually a 1T isn't it? - 3400 is 3/4T
wasn't there some modern swap for the rear on 1T? I think you'd have a hellofa time swappin in 1/2T axles on that frame - more like the 5spd that Jeff suggests, and then a roof vent and onea them neat window mount swamp cooler things from the 50's to happy up the co-pilot

Bill

Tony, don't know much about the big panels. my 52 half ton as I have mentioned before has a 85 blazer rear end, got to keep my 6lug wheels and it has an 88 s-10 5 speed with overdrive, the rear end has 2:73, I do lose a little on take off but I like it fine, it will run what ever on the highway and get about 21 mpg. it is only turning about 1,500 rpm at 60, a whole lot less strain on the motor, previous with the patricks 3:55 and the patricks modifed 4 speed sagniaw it would turn about 3,200 at 60, I drove it about 6 years before the old enclosed drive broke, it was quick though but you just felt that you still needed another gear on the highway, a lot drive them with this set up. I like the conversion best because my min trip on the interstate is about 65 miles one way, now that I have got use to it, I would not be afraid to drive it any where. sorry, I know this is more then you wanted, do you and cletis live near one another? I would like to meet you both and see your trucks, let me know when and where? Fred

Tony, the cheapest way to get "longer legs" is to swap out the 5.14:1 for a 4.10:1, which came in later versions of that axle. This will give you a cruising speed around 45-50 mph without straining the motor. If you want better (lower numerical value) than 4.10's you will have to change the whole axle or have a ring & pinion custom made; both options are a huge investment of time and $$$. Think of all the fabrication involved in putting 1/2ton hardware under a tonner frame... if you're going that far you may as well upgrade to IFS and front disc brakes.

Nope, I don't think IFS makes you go any faster.

Tony M, have you had time to do any work on your 54? keep us posted....Fred

It should be soon I hope. Right now I am fixing up our bathroom. (honey do) I am also going to put in a second driveway to hide some of my vehicles in the back. At the same time I will roto everything and get ready for a garden for the kids and put in the pond. Let's see, right after that I should have some time...

At least the truck is doing it's job right now. First thing I am going to change the tierod ends. I am really worried the truck will go in two seperate directions one of these days.

Boy, you do have a busy plan,take care and nice to hear from you....but remember, you always have time for things you place first..Fred

Tony: I have a 53 3800 1ton panel and use it and drive it almost everyday. I dropped a 261 into it, added a 4.10 chunk in place of the 5.14 and swapped in a t5 with a .73 OD from a Camero. The truck will run at about 2000rpm at 60mph and can go alot faster with ease. I normally get about 15-17 mpg in town and 18-19 on the highway. I added a dual master cylinder but am going to change that to a power master this summer because Ruby will easily out drive the brakes.

Tony,

You want to look for a '67-'72 GM (Chev or GMC) 3/4 ton pickup with an automatic. It will have coil springs.

That will have a 4.11 rear gear and it will take you less than two hours to do the swap. I drove my '51 at 55-58 mph all the way to and from Syracuse on this rear end and it is heaven for the original 5.14 stump puller owner.

Here's a link to how I did mine:
3/4 and 1 ton rear end swap option - Get it up to 55 and drive comfortably.

Sooo, what is the difference between a pick-up rear end and a blazer rear end?
thanks
tony l.

Depending on the year, a two wheel drive pickup rear end will take five lug wheels while a 4WD and Blazer axle will take 6 lug.

Were the Blazers or S-trucks available with 3.08? I'm looking for a 3.08 rear with six lugs for my 261 powered SM420 shifted truck.

Can't speak for the S-trucks(that's a pretty light duty rear end anyway) but my '84 K10 has 2.73 axle ratios in it so I imagine that 3:08 was available also. When the K10 finally gets too rusty to be safe I think I will have the rear axle rebuilt(190K miles on it now) and put it in my '37. I have a late fifties corporate HO33 rear axle with Patrick's 3:38 ring and pinion in it now, but running a 235 with smallish tires I find the gearing still too low without an overdrive(I use a SM 420 tranny also). The 2:73 will probably be just right. Shouldn't be too hard to find a 3:08 corporate 10 bolt or Dana 44 from a K10 or Blazer in the junkyards.

I am doing a swap using a rear out of a '76 Chevy K10 4X4, which has a 3.07 ratio in it.

Tony , you might call your local chevy parts dealer, I did and he gave me all of the rear gears for my 85 blazer, sorry but I lost mine, I think they must have been about 6 or more ratios,
...Fred

remember that you guys are comparing totalyl different axle models here

4.10 was the eaton ratios back in 72 and older 3/4 and 1 ton, optional for boh models, 4.57 was std equipment ratio through at least 72 anyways

1/2 ton rears were the 8.875" 12 bolt starting in 64 and the 8.5" 10 bolt starting in 82 for most 1/2 tons

64 and 82 were the two 1/2 ton axle conversion years, 73 was the 3/4 ton and 1 ton conversion year

dana 60 found under 67-72 were std equip of 4.56 and optional 4.10 and very optional 3.54

most all were under 3/4 ton with coils and mostly under leaf

eaton and dana were both 10 bolt covers, it can and does get confusing for the novice

three 10 bolt, technically four ten bolt model axles all very different from each other if youy count the 67 68 gmc 1/2 ton 44 axle too..

dana 44 are 8.5" gear also.

s-series used a whole other 10 bolt, the 7.5" smallest 10 bolt. and there was a 7.625 oddball axle under some light series, i am unsure which though.

and there are some 8.5" 10 bolt with 12 bolt gear under some caddy cars to help make it more complicated for you.
and then the B&O type axles for even more complication- bearings pressed to shafts instead of on ends of tubes

but quickest fix on your deep ratio problme is to find an eaton H052 or H072 with 4.10 in it and swap that carrier on your axle, thats as long as it still has Eaton axle under it with removeable carrier, 47-72 years, look for the 67-72 C20 and C30 trucks, dually or not, both used the same two models of eaton axles and same size carrier, try to snag one form under a pickup bed trailer for cheap or find a parts truck 67-72 c20 or 30, a few K20 trucks have eaton rear but most were dana 60 rear.

For another guy who can give feedback on the swap contact WallyMT. He is or has done the same swap. I think he has been in Washington State for the last few weeks.
These drop-in rear differentials are pretty darn tough. I think with a regular oil change every year or two it will last longer than most of us

only thing ot worry about on he H052 and 72 models is the price of brake parts if even available, and also keep eye on pinion stem bearing, they liek to burn up if fluid drops just low enough, keep tight tabs on that oil level in that axle! make sure the pinion yoke and stem does not move side to side when you get udner there and yank away on it, yank and push hard ot make sure !