The Stovebolt Site Forums The Shop Area Engine Shop open drive shaft rear upgrade

Hi I have a 1952 AD pick up and would like to put a rear end in it that has a higher gear ratio and an open drive shaft.I have a 1955 235 engine and 4 speed trans with granny gear,can anyone who has done this let me know what rear they used,the junk yards we have here are called recycle yards and they dont let you go in and look around or make measurements,so I need a specific car year and model to ask for to get the rear that will work Thank You for your help

The easiest thing to do is get the removeable pumpkin from a 1955-61 Chevy 1/2 ton and replace your pumpkin/torque tube with it. This will require that you weld up the hinges where your rear spring u-bolts are located,

Here is a list of axles.

axles

Hey thanks Lonnie, nice information, need to keep that in the tips section. Now I wish there was one like that for the transmissions.

WD, so are you saying that you can use the later carriers in the original 1/2 ton AD axle housings? I would think that you would need to check all of this with inspection tools to make sure the center lines are correct. Do you know for sure that the axle center line is the same in both of them? And what axles do you need to use for this swap?
Denny Graham
Sandwich, IL

i used a 79 nova. the gearing in mine is ok for flat land but a little low numerically for hilly country, it is 2.73 with a t-5 s-10 tranny. in fourth it does ok but in 5th it lugs a little. ron

Well I can't imagine having a 2.73 with my '50, 216. I just finished putting a 4.10 in her and it's fine, there is a noticeable difference in the pulling power from the 4.57, I just don't have the acceleration I did before. I had thought a 3.90 would be nice but am having second thoughts about that now, might be ok for a 235 with more horses but I would say that would be about the limit for a 216.
Once again, a 3.55 with a 216 I'll bet is a real dog and you would be really lugging it down and a 2.73 even with a 5speed would be a real pooch.
Denny Graham
Sandwich, IL

Faster gears are ok for bigger engines. A stock 216 won't pull anything faster than 4.11. A 235 will handle 3.90 which is available in 1954 as a closed drive shaft and 55.2 as an open drive shaft. Patrick's makes a 3.55 kit for the closed drive setup. I enjoy acceleration and I think that is the limit for a 235 and you would give up a lot of acceleration which I am not willing to do. Faster gears than that you will build a critter that runs 40 up hill and 80 down hill. And that's no fun. That's how big trucks were 50 years ago when I started driving. If you want faster gears, I would recommend a bigger motor. Either a v8 which takes a lot of doing to install or going to a GMC 270 or 302. They are relatively simple to install. They are about an inch and half longer than a Chev, but that is relatively simple matter. For something just to drive, I would think a 235 with a 3.90 would be a good all around ratio. A 54 closed drive shaft, it would be a bolt together. Going to an open drive shaft is relatively simple. You need the open drive shaft transmission and as WDOF mentioned, you have to weld the hinges at the spring hanger. WDOF has a good picture of how that is done.

Chevrolet 1/2 ton axle shafts are the same from 1951 to 1961 same part numbers. This is a swap that has been done many times, It is cheap and easy, I can even send you a photo of the hinge modification if you will send me a regular email. (I can't post a photo through this system)

[email protected]

Denny,

The axle list is in the tips section. That is what I am linking to.

Lonnie

I have driven many thousand miles in a 1/2 ton 235 w/3.90 gears and never thought it was too slow, even on the freeway. Of course that was many years ago. To day if you drive 65mph you get run over on the freeway. I am planning on 3.55 at some time in the future.

green48,

Look for a gm 1/2-3/4 ton 12 bolt from around the late 60's to early 80's. This site calls it a GM Corporate 12-bolt. I don't have a width for you, but mine fits great, has 6 lugs for the original wheels, and a 3.07:1 ratio.

The "How to Restore Your Chevy Truck" book has a picture of a red one in it somewhere.

I beg to differ.

My stock 216 was a joy with the 3.55 R&P. To me, the most significant difference was having to downshift into 2nd (SM420) around town, but on the road and acceleration-wise (yea, like since when did a 216 and acceleration become part of the same sentence?) I was very pleased with the performance and would readily recommend the 3.55 in a half-ton with SM420.

In fact, I canned the idea of going with a Muncie because of the performance with the 3.55 and SM420.

was the 355 rear you used open or the closed type with patricks gears?

I installed a 3.90 rearend behind my stock 216 and I don't have any problems with pulling.

Patrick's ring set is for a closed drive shaft. I have never owned one, but I have helped build a couple up. SM420's are geared so low that the 3.55 gears probably help them. However, I just can't imagine a 216 having any spunk at 50 in hi gear with 3.55s. But then again, I grew up in the days when pickups sounded like they were going to fly apart and now I guess now I just don't hear them. But I still like to give it the gas at 50 and feel some power.

Quite frankly if I gave my 216 "the gas" at 50 it would have probably exploded...

Closed... I like my driveline stock... within reason, of course.

I never drove a Chev but I know there was a point where dippers wouldn't oil the rods enough. I drove a 1950 GMC to school all four years of high school. I had all kinds of motors -228 248 270 and 302. I cracked a few heads from having a stopped up radiator, but I never had one to thrash out on account of over revving. I remember getting a ticket for 82 and that was with a 4.56 3/4 ton rear end.

Man, that's insane... There is no way I could imagine going 60 let alone 80 in mine with the 4.11... that must have sounded like a P40 in a power dive.

At my age I'm perfectly content putzing along country roads at 45 with Uncle Dave Macon blaring on the radio.

I think the Lone Ranger pulled a fast one on ya good buddy, that combination would have your six popper reving at well over four grand at 82mph.
I just put a 4.10 in my 1950, 3604 and now she feels real happy at 55mph. Runs about 2600-2700 depending on which tires I've got on her, i.e., 28.5" or 30".
Denny Graham
Sandwich, IL

crenwelge never said what tranny he was running at 82 mph...it's possible.

No but, I've gotten the impression that out friend from Texas, like me isn't a youngster and when I went to high school in the 50's unless you had an over drive tacked on the back of your trans, you were limited to a 1.1 high gear in all the transmissions.
Man am I argumentative this morning or what!!!! That’s what happens when I can’t finish up a simple task on the truck….
Denny Graham
Sandwich, IL

Ha! I'm with you there, Denny.

A few days ago I saw a tree branch that needed trimming, so I grabbed a pipe...

My father used 3/4 tons in his business that came with 4.56 rears. He installed 7.50x17 tires which are about 33" diameter. They all had sm420's. My favorite setup was a 270 with a 302 intake with a Stromberg WW. I had a 302 with a 3-1 setup, but it required constant tinkering. There were years in the late 50's when Texas issued driver's license to 14 year old kids. I got a commercial license to drive an 18 wheeler on my 16th birthday in 1959. Just because 228's had advertised hp at 3200 and 248's at 3400 doesn't mean they wouldn't go faster. Running them over 4000 was no big deal. Nothing ever happened to the bottom end. The trick was to keep the water below 200 and have strong enough valve springs to keep the valves from hanging open. That's why GMC's were popular with the serious dragsters and some 270's even ran at Indy. Driving like that was very unsafe. Brakes wee almost useless at 80. A puff of wind from the side could blow you over to the wrong side of the road. And we disregarded engine and wind noise. In those days I only spoke English when I had to which was in School. We had a saying that translates to "just don't drive any faster than your guardian angel can fly".

Green48,
If you want pics of this swap I have the whole process pictured on my Flikr site - removal, cutting, welding, all the way to install. Steppenwood(Jon in Cali) has a good set of pics as well. I did mine followin his picts. They are both 46's but the closed to open DL and punkin swap should be similar.
My option was t-5 and 3:90 punkin and saddles out of a 55 1/2 ton. I second wdoftexas comment, this has been done many times, is cheap and imho, the easiest way to go. I did mine in two days. Search the archives, but the pictures are pretty much a step by step set of instructions.
Cavebull