The Stovebolt Site Forums The Shop Area Engine Shop small block question....

I have a '50 Chevy 1/2 ton five window that I'm restoring. I would like to run a small block (327) and automatic trans (700R4). I would like to make around 350 hp. out of the engine and I'm wondering if I can use the original torque tube rearend with this combination? I would change the gearing to 373s for those highways:-) Is this a wise choice? If so, what mods would I have to make? Obviously I'd need new tranny and engine mounts, but what other mods would I need to do? Any help would be greatly appreciated!

NOPE.............

You'll have to run an open rearend, so you'll need a rearend & a drive shaft..Joe

The transmission change dictates that the driveline be different and the driveshaft change dictates that the rear end be different. These are the first of many many steps on the path of modifying a vehicle vs restoring a vehicle. One thing becomes four and four become twelve and so it goes. Cubic dollars will solve it all however.

Wel put Dave cubic dollars

My question is, why not???

All the SBC engine requires is a change of bellhousing to make his original transmission work. The torque tube goes from the tranny to halfway back to the rearend, doesn't it? Then you get a regular driveshaft from where the torque tube ends to the differential.

It's a simple matter to change out the diff for one that has 3.73 gears, and then get a yoke put on the driveshaft to match the size on the new diff.

Sorry, but I don't see the problem. In fact I've done exactly that on my truck, with a 350 in it.

The only thing is, the position of the stock tranny puts the new engine too close to the firewall. You can't use an HEI without some firewall clearancing, and if you ever think you'll need to pull the valve covers off, you'll need clearancing for that too. Then mount the new motor mounts wherever that puts you.

The bellhousing you'll need to find was made in the 70's, and on the tranny side it matches the 4 bolt pattern, and on the engine side, it matches that bellhouse bolt pattern. I did have to cut my bellhousing to make room for a conventional starter though.

I used a 10.5" Corvette flywheel (60's vintage) and a brand new clutch. Even the spacing for the clutch fork was exactly the same...if you use the inline six's throw-out bearing.

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Correction...I did not notice he was changing the tranny. Sorry I misread the original post. Please see my new response below...

Okay I'm mental.

I did NOT read that he was using a 700R4 until I re-read it.
SORRY. Okay, then NO, you can't use the torque tube. You'll have to get a driveshaft made for the right length.

The advantage to using the new tranny is that you can position an automatic for the best engine location, so that none of that firewall clearancing would be necessary.

One other problem is that the truck in question is a 1/2 ton. The torque tube goes all the way back to the diff, unlike the 3/4 tons.

...and Hot Rod Dad, he said it's a 1/2 ton so there is no half and half driveshaft. Your thinking of the 3/4 ton set-up I betcha.

Anything is doable with good planning

Anything is doable with good planning and enough money!

Don't feel bad Hot Rod Dad, I missed the 700R4 the first time too, and was about to post a why not like yours.

If anyone mentioned the common exhaust manifold to steering box interference problem I missed it. That's another problem that has to be solved to make this swap work.

"steering box interference problem".....
Just last night I say SOMEWHERE here on the bolt pictures of the steering situation which has been discussed much here the past several months. I, myself, have been watching, reading,posting about this as I am putting a 350/350 in my panel.
The pictures I looked at last night showed a simple plate bolted to the chassis moving the steering column out 1 1/4 inches. then the steering box mounted on the plate.
Question arises if the steering wheel sits good and someone answered he had did this and could tell NO difference when he drives his truck. Another bolter said he heated the firewall cherry red and then pushed the column over making sure it had plenty of room....so it CAN be done fairly simple and retain the original steering box.
Next this bolter used a set of manifold that came down and exited out the back. I looked close and there is room to get to plugs ect and the manifolds can probably be gotten for cheap. He didn't say what they were off of but I'm sure a junk yard search would find many.
Perhaps this would be a good tech tip if I could only remember what forum/who made the post and get them to write one.
I know also that a (toyota) steering box can be mounted on the side of the chassis and get power steering. You will most likely have to cut a small section out of the inner fender to run the steering rod to it but the pic I saw of this worked very well.

The best part about the Bolt is that you can usually always get FIRST HAND information of what has been done and save a lot of trial and error...to those who have already done this and posted it for us I want to say...THANK YOU.

Hi guys,
thanks for the info, guys. I would consider running the original 3 spd....if that would allow me to use the original rear diff and torque tube. I didn't know it was possible to run the 3 spd w/ a later small block. I like the 700R4 for the sole reason of the low rpms on the highway.....but I have a budget to consider also:-) However, after reading some posts on here I've found that using a rear diff from a '57 chevy would be a near bolt-in...after moving the spring perches to the top. Amazingly, my father has one of these (rear diffs) sitting in his garage. Anyone have any tips for putting this in the truck? I'm thinking this would allow me to run my small block and 700R4....and just have to have a driveshaft custom built to fit. Again, any info on this would be greatly appreciated. Thanks!

nastbscott: For my 52 panel, which is "in process" I pulled the axles out, then pulled the complete torque tube assembly out and layed it outside the shop. Then I bolted in a "pumpkin" from a 56 chev pickup. My axle bearings are good so bought two new axle seals and re-installed my original axles. Its still a 6 lug but I also have 4 rims that are 6 lug 15" that I'm using.

As for the 700R4 it ia a good tranny and I have one in my 37 BUT a friend of mine who has, along with his dad, built transmissions for years says the "simply" and best way to go is to run a 350 automatic that has overdrive. I believe the year he quoted me was a 1987 up. He explained to me why the 350 would be best for my use but can't remember all the details as to why. So, I'm thinking about 350 for my panel that has overdrive! He says wiring is simple and it has less Coils(?) and will adjust easier.....I just can't remember all the specifics but I trust his word. He also build tranny's for rail dragsters and about everything else. Maybe someone here can contribute more to this than I can explain?
I might add that going from my original torque tube rear end gets me from a 4:11 gear to a 3.90.....I am not sure what it would be in the end running a regular 350 tranny or one with overdrive...but I'm going to find out!

Thanks again...this is a great help to me! And, I really want to keep the original six lug rims. I'd like it to look as original as possible from the outside, but just don't want the 'ol 216, 3 spd, and torque tube as my drivetrain. Being a muscle car fan and restorer, this is my first restoration on an old Chevy p/u....so all info helps:-) However, I need to clarify something from your previous post....did the '56 pumpkin bolt up to the original rear diff from your '52. Or...did you use the entire rear diff and pumpkin from the '56? This may be a dumb question...but i'm having trouble picturing what my original rear diff looks like on my '50. Also, the rear diff I have access to is from a '57 chevy car (Belaire...2 dr. post)...will this still work? It has the "pumpkin" that can be removed....just thought I'd check. Thanks in advance.

The TH350 was never made with overdrive. There was a few years that had a lockup converter, about '84-'87 I beleive, that was called the TH350C. Those transmissions are generally considered junk as far as performance terms.They were probably thinking of this trans (the converter lockup could be counted as either an additional "shift" or maybe and "overdrive" because it drops the rpm some). The 700R4 is the closest to being a 350 with an overdrive, as it is heavily based on the TH350.

Longbox, you may be right. Seems it was a "lockup" type but when Paul speaks most folks listen. Perhaps he knows, or does something, that most folks don't know. I will be back up his way in a few days and will discuss it with him again. I like the 700R4 that I put in the 37....I was running a regular 350tranny before that.

Nastbscot: the 56 "pumpkin" I used bolts right in the original housing and you use the same axles. I'm not SURE about the complete 57 rearend working under the AD but I feel sure it will. Just have to look at the mounting perches and see. I'm sure someone here has actually done it so stayed tuned.
Note: if I had acess to a "free" complete rear end I would have taken my original housing out. Since I'm leaving it in I will have to weld the "swivel" were the rear end could swivel up and down some due to having the torque tube instead of an open drive shaft. It may sound real complicated but when you take a good look at yours you will see what I mean.

I would also put in a later model "pumpkin" if I could have one to get a higher gear than the 3.90 I will have. But it will not be hard to change the pumpkin again if and when I ever run into a real bargain!
Hope I have not confused you more?!

Another choice could be a 2004R which was generally used beind
V-6's and is shorter than the 700R4/4L60. They used this trans in the Buick Grand National so they hold up ok.
Fred

You could use the torque tube rear end, but you can't get a transmission that will hold up to a hot 327 that works with the torque tube. You will have to go to an open drive shaft to get a trans that will take the power of a 327.

thanks again, guys. But, one more question...if I bolt the pumpkin I have (from the '57 belair) and use my original housing and axles...wouldn't that allow me to use a drive shaft and scrap the torque tube? Sorry for all the questions! Thanks again!

YES......
just to clarify: I used the pumpkin out of a 55/56 TRUCK....if the 57 car is the same then you are good to go. I just don't know for sure if there is any difference in the rearend from a 1/2ton pickup and a Belair.
More questions! Are the truck/car rear pumpkins the same?

IIRC, the 55-64 passenger car rear end center sections interchange, but they do not swap with the pickup center sections.
Jerry

Good to know! I'll likely swap the entire read diff (from the '57 belair) into the truck and get rid of the original. Any tips on what I'll need to do to make this swap? I read on here that I'll need to relocate the spring perches from the bottom to the top. Once again...any advice would be greatly appreciated. Thanks!

If you're keeping the original front axle setup, you'll have 5-lug wheels on the rear, and 6-lug on the front. I think there may be a way to adapt to the same lug pattern on the front by swapping hubs, but it's been a long time since I've done it. Swapping to a later model subframe with IFS and disc brakes makes more sense on a hotrodded stovebolt. It needs to steer and stop and handle as well as the V-8 makes it run. I'm about to build a 76 Nova front/S-10 rear frame combination, with a 54 stovebolt cab and bed on the late-model running gear.
Jerry

to change the front hubs to 5 lug you can use the hubs off a car. I think the 55-56-57 car will fit right on his truck. I did this once but many years ago. I think use the car hub and bearings.
Its no big deal and someone will come along shortly that knows for sure what years. But, as mentioned you may want to consider your options based on what your running or planning to do.

Actually the 51-54 pass car will work on the 1/2 ton pickup. The hub and spindle are longer than the 55-57 car. It still would be better to convert to disc's if you are going to have some serious HP.
Fred