Stock rear end with a V8

[ratfinkxxx]

Swapping in a mild small block with o.d. transmission. Will the stock rear end hold up under normal conditions?

[Adam H P15 D30]

Yes, what are you planning to do for a parking brake?

[kencombs]

IMO, the OD trans would be weaker than the differential.  Drive with reasonable care and it will  be fine.  Lots of tire smoke, quick clutch releases or speed shifts, all bets are off.  The early V8 cars and trucks had essentially the same drive train.  I used to do a lot of mechanic work in  the 60s/70s and I can't remember changing a rear end on a Mopar.  The other two of the big 3, changed a lot!

 

edited to add:  To illustrate my point, one of my favorite cars was a little 65 Dart with the HIPO 273/4 spd.  Needless to say it got driven with spirit shall we say.  It had a 3:23 from the factory and I swapped in a 3.55 from a 55 Chrysler. Swapped side gears to match my axle splines but otherwise just as it was remove for a 100,000 mile car.  Drove it for 5 years without issue.

Edited August 17, 2021 by kencombs

[Loren]

I am a big fan of the stock 8.25 rear end. (1937-56)

However, your 1936 has a different rear axle that I do not have experience with.

I believe a 1937-56 8.25 could handle a V8 as they were used in a lot of cars that had them.

My M.O. is to make a change AFTER the stock part has been proven to lack the needed strength. The old "if it works don't fix it" motto applies.

 

As far as the Overdrive transmission is concerned I am a huge fan of those too but again there's an age problem. The R10 Overdrive that most of us are used to can be installed easily in a 1940 to (what?) 1956 because of the column shift. A 1936 might be better off with a T5 because of the floor shifter. People who know me know I dislike T5s intensely. The reason is most are sourced from S10 pickups (because of the shifter location) and have the worst ratios ever.

 

So how would I approach this?

I'd be seriously questioning myself as to why I wanted a V8.

In the end I think you'll be changing everything and it might be better to get a later car (1940-41?)

There's no way I can see what vision you have for your car.

Just know anything is possible but even if you can, should you be doing it?

More power, more reliability might be had from a later 230 Plymouth or Dodge flathead six and that would be a lot easier and cheaper to do.

[Andydodge]

I'll add my 2.8(due to the current exchange rate)cents worth.........here in Oz the 1957-62 Chrysler Royal was basically a 1954 Plymouth with 55/56 Plymouth front & rear sheetmetal and the 313 canadian Poly V8 & torqueflite or 250 cube six installed by the factory.............when I hotrodded my 1940 Dodge I bought a 1962 Chrysler Royal and installed the 313 Poly/Torqueflite and 1962 Chrysler Royal rear axle........this rear axle was an 8.25 with 3.31:1 ratio, I had this rear end in the car from 1973 to around 2005 when I replaced it with a 1990's Frod Falcon rear axle..........during the time the Chrysler Royal rear end lived in the car it had no issues, and was only replaced due to problems with the outer axle bearing that necessitated its replacement........so I'd think there would be no real issues swapping the rear ends............andyd.

[Sniper]

5 hours ago, kencombs said:

IMO, the OD trans would be weaker than the differential. 

 

OP doesn't say what OD trans or for that matter what brand engine.  Might be a 350 with a 700r4.  Might be a 360 with an A833OD, heck it could be a 302 with a T5.  We don't know. 

[dpollo]

A friend used a 322 Buick in his 41 Plymouth back in 62.   All Plymouth from the flywheel back.    Same today.

 

In my experience, axle failure ( LHS) was rare and usually 50 to 52.  The 37 to  48s were very good units.    The parking brake, or lack thereof can be solved by mounting the drum and band on the input shaft of the differential.   A disc brake might be preferable.  

[kencombs]

1 hour ago, Sniper said:

 

OP doesn't say what OD trans or for that matter what brand engine.  Might be a 350 with a 700r4.  Might be a 360 with an A833OD, heck it could be a 302 with a T5.  We don't know. 

You're right of course.  I sort of assumed a manual 3sp w/od.  That said, with the exception of the a833, all ODs are weaker than the diff in IMHO. The 700r4 had a terrible reputation in the early years. More than one locked up without warning at highway speeds due to OD gear/bushing lube deficiency.

Edited August 18, 2021 by kencombs

[allbizz49]

After the time and expanse of swapping in a v8, why skimp on the rear end? Plenty of good axles out there sitting in junk yards for cheap. Perches are under 20 bucks. 

[ratfinkxxx]

Ranger 8.8 rears are going for $350 here. I bought a rebuilt 350 for $700. Got a used GM reman 700R4 for $400. Can't find 230s. I have tried. Even if I could the a trans upgrade would be necessary to run highway speeds. I'm going the cheapest route I can to get a decent driving car. Based on what I have read here I will run the stock rear. Thanks to all for your input.

[Bob Riding]

22 hours ago, Loren said:

I am a big fan of the stock 8.25 rear end. (1937-56)

However, your 1936 has a different rear axle that I do not have experience with.

I believe a 1937-56 8.25 could handle a V8 as they were used in a lot of cars that had them.

My M.O. is to make a change AFTER the stock part has been proven to lack the needed strength. The old "if it works don't fix it" motto applies.

 

As far as the Overdrive transmission is concerned I am a huge fan of those too but again there's an age problem. The R10 Overdrive that most of us are used to can be installed easily in a 1940 to (what?) 1956 because of the column shift. A 1936 might be better off with a T5 because of the floor shifter. People who know me know I dislike T5s intensely. The reason is most are sourced from S10 pickups (because of the shifter location) and have the worst ratios ever.

 

So how would I approach this?

I'd be seriously questioning myself as to why I wanted a V8.

In the end I think you'll be changing everything and it might be better to get a later car (1940-41?)

There's no way I can see what vision you have for your car.

Just know anything is possible but even if you can, should you be doing it?

More power, more reliability might be had from a later 230 Plymouth or Dodge flathead six and that would be a lot easier and cheaper to do.

That's just what I'm planning to do with my 1940 stock Plymouth wagon- install a '56, PowerFlite 230 with the "Power Pack" from a 2 door Suburban donor car. (The woodie currently has a 218 from a P20, so I should pick up at least 30 hp)

 

This thread made me think about also swapping out the rearend or maybe just the gears. I also have another '56 Suburban parts car- this one has the 277 V8 and a gear ratio of 3.54 - the PowerFlite 6 has a 3:73 ratio. Do you think there would be much advantage in swapping out the stock 4.1 gears from the '40 (it's got an OD that works well), with either the 3.73 or the 3.54?

[Loren]

Wow!

You have three desirable cars!

My 1949 Business Coupe came with a 218 and 3,73 gears. I've put an Overdrive in it and I think it's great!

Suburbans are heavier (the Coupe being the lightest Mopar) but even with the 201 it should be able to pull 3.73 gears. You might see more Kick Downs with your Overdrive however in hill country.

That said a 3.54 is not a huge difference and with the 230 Power Pack it would be ideal. BTW the Power Pack Bendix-Stromberg WW carburetor is my all time favorite. 

Here's the best part about your plan: You don't have to dismantle the whole car to change gear ratios. You can just change the Differential Carrier NOT the whole axle. Which means if 3.54 is too tall a gear for your area, all you have to do is change the Differential Carrier to the 3.73. Much easier than changing whole rear axles or pulling them out to change ring and pinions. Plus if things change (like if you move to hill country) you have a selection of gear ratios on the shelf ready to go.

You have options!

The question becomes Overdrive or Automatic.

If you still have the original 1940 gear box it may still have the one year only second gear ratio the old time Hot Rodders prized. (The Ford guys had their version too. If you heard an old timer talking about Lincoln Zephyr Gears, that's what they are. LZ gear sets are going for $600+ now days)

So you have much to play with! Enjoy!

[blucarsdn]

ratfinkxx, To reply to your question regarding a rear end to use under your '36 with a 'mild small block and a O.D. trans'?

A lot of people have replied with a multitude of suggestions, the majority of which are based on what I call old school junk yard donor technology. For the most part the days of going out to the local wrecking yard, to harvest a Mustang, Gremlin, Duster, Volare, etc., suspension, drive-train are long gone.

Putting a mild small block. GM or Mopar with an OD in front of a 85 year old rear end should be the least of your worries. How do you intend to stop/control the car the car? The suspension under your car is/was designed for 45/50 MPH.

I was faced with the same problem you have when when I acquired my 39 Plym conv coupe. The car had been sitting for 38 years in an open field in Montana, the suspension, etc., was junk and several of the frame cross members were broken broken. I wanted a car that I could safely drive at highway speeds. To that end the body was removed from the chassis, the frame was stripped down to a basic frame, a new Fatman front end assembly was ordered with power disk brakes, rack pinion power steering and Posie rear suspension. I purchased a new 2003 SBC 330hp crate engine a new 7004R trans and a new 10 bolt GM, 54-1/4" backing plate to plate rear end with 325.1 gears.

My car is a pleasure to drive, cruising very nicely at 70+, windows up, AC blowing and nice tunes on the radio. Wm. 

[Bob Riding]

1 hour ago, Loren said:

Wow!

You have three desirable cars!

My 1949 Business Coupe came with a 218 and 3,73 gears. I've put an Overdrive in it and I think it's great!

Suburbans are heavier (the Coupe being the lightest Mopar) but even with the 201 it should be able to pull 3.73 gears. You might see more Kick Downs with your Overdrive however in hill country.

That said a 3.54 is not a huge difference and with the 230 Power Pack it would be ideal. BTW the Power Pack Bendix-Stromberg WW carburetor is my all time favorite. 

Here's the best part about your plan: You don't have to dismantle the whole car to change gear ratios. You can just change the Differential Carrier NOT the whole axle. Which means if 3.54 is too tall a gear for your area, all you have to do is change the Differential Carrier to the 3.73. Much easier than changing whole rear axles or pulling them out to change ring and pinions. Plus if things change (like if you move to hill country) you have a selection of gear ratios on the shelf ready to go.

You have options!

The question becomes Overdrive or Automatic.

If you still have the original 1940 gear box it may still have the one year only second gear ratio the old time Hot Rodders prized. (The Ford guys had their version too. If you heard an old timer talking about Lincoln Zephyr Gears, that's what they are. LZ gear sets are going for $600+ now days)

So you have much to play with! Enjoy!

Great info. I like the idea of going with the 3.54 first. I don't remember if I used the original gearbox that came with the wagon (the whole thing was pretty trashed from sitting in the desert for a few decades) but I had George Asche rebuild it and add the overdrive. Is there a way to ID it to find out? Oh and why is the Power Pack Bendix-Stromberg WW carburetor your all-time fav?

[Loren]

Bless you for saving this marvelous car!

 

I was turned on to these carburetors from a guy who specialized in carburetors.

He had once held a license to build Stromberg 97s and thought the WW was a much better carburetor.

He proved it by put them on all sorts of cars from Mercedes 450SLs to my little SAAB 96 V4.

The SAAB set a class record at El Mirage Dry Lake of 117.42 mph way back in 1978, breaking a record that had existed for 20 years.

WW carburetors are found on so many cars I can't list them. Bendix-Stromberg also sold them as replacement carburetors for cars that didn't come with them and I can't imagine that the performance wasn't improved by using one.

The Power Pack manifold added a bunch of horse power and it was so simple. One carburetor and simple linkage to deal with. Of course if you wanna trade I have an Edmunds or an Offenhouser manifold I'd trade for one, might even throw in a couple of carburetors too. lol

[Bob Riding]

Tempting offer..As I get closer I'll let you know...

 

[ratfinkxxx]

bluecarsedan I asked a specific question about the build.This is a budget build. My car is a rust free survivor. Brake upgrades will be addressed. I feel the suspension is more than adequate to handle highway speeds. I wish I had $50k to throw at a car. My goal is a car that could have been built in the 60s. The way it used to be done. Thanks for your reply.

 

[Andydodge]

The main thing from my perspective after living with my 40 Dodge for 50 yrs is that whether its "old school junkyard donor technology" or high end current tech is that it be done in a correct and safe manner...........Yep, my car is old school I suppose....I bought a complete 1962 Oz Mopar, pulled the engine/gearbox/diff and installed the lot with a rack & pinion steering in the 40 Dodge, over the next couple of years firstly 11" vented discs went on the front and soon after 11 vented discs on the mopar rearend & dual circuit boosted master cylinder..............By the late 70's it also had a collapseable steering column, seat belts front & rear, child seat mounts, heater/demister, 2 speed wipers and a few others odds & sods........the thing is that old school tech can work just as well as new school tech............so long as its done in a safe manner its all good..........and just to make it clear.................thats a very nice 39 Plymouth Convertible, a real credit to you................Andy Douglas    

[Adam H P15 D30]

20 hours ago, Bob Riding said:

That's just what I'm planning to do with my 1940 stock Plymouth wagon- install a '56, PowerFlite 230 with the "Power Pack" from a 2 door Suburban donor car. (The woodie currently has a 218 from a P20, so I should pick up at least 30 hp)

 

This thread made me think about also swapping out the rearend or maybe just the gears. I also have another '56 Suburban parts car- this one has the 277 V8 and a gear ratio of 3.54 - the PowerFlite 6 has a 3:73 ratio. Do you think there would be much advantage in swapping out the stock 4.1 gears from the '40 (it's got an OD that works well), with either the 3.73 or the 3.54?

I would put the 277 V8 in and leave the 6 in storage.

[Loren]

My Mom had a 1955 with with the 277 V8 and a PowerFite and it was wonderful car!

I wish she had saved it for my first car but she sold it for $15!

It was absolutely reliable and a great looking car.

It was a Red and Black 2 door hard top, very snazzy! Or at least I thought so from the first time I saw it, till the last time.

Oh and you can put a Bendix-Stromberg WW on it to good effect! Just say'n.

If you have to put a V8 in your 40, I'd have to approve that one for purely sentimental reasons. lol

But that is what the car hobby is all about...how your car makes YOU feel.

I admit I go out to my 49 and open the door just to see the new clock ticking away and keeping perfect time!

That makes me happy!

[kencombs]

3 hours ago, Adam H P15 D30 said:

I would put the 277 V8 in and leave the 6 in storage.

Me too.  Now.   In my misguided planning for my 56, I discarded a 277 that I had bought for another project.  It needed everything but was a good core.  Before I found out that certain clutch housings would accept the flat 6, early hemi, and A engines I got rid of the 277 because the machine work and parts were expensive.  And they are, it's just that now I think it would have been worth it.  I've looked for a running A for a while, but have resigned myself to using the six.  However, I am using the correct crossmember, clutch housing and a transmission that will be a perfect mate for a small v8 should one become available at a great price.

[Bob Riding]

2 hours ago, Loren said:

My Mom had a 1955 with with the 277 V8 and a PowerFite and it was wonderful car!

I wish she had saved it for my first car but she sold it for $15!

It was absolutely reliable and a great looking car.

It was a Red and Black 2 door hard top, very snazzy! Or at least I thought so from the first time I saw it, till the last time.

Oh and you can put a Bendix-Stromberg WW on it to good effect! Just say'n.

If you have to put a V8 in your 40, I'd have to approve that one for purely sentimental reasons. lol

But that is what the car hobby is all about...how your car makes YOU feel.

I admit I go out to my 49 and open the door just to see the new clock ticking away and keeping perfect time!

That makes me happy!

I know what you mean about the sentimentality-I've been accused of that myself...I've seen pictures of the '56s with the red and black color scheme, and it is the best of the palette that Chrysler  came out with that year. As for the V8 swap, I don't think I could do that to the old girl!  I think the Power Pack 230 combo will be a big improvement. Besides, how fast do you want to go in a car made of toothpicks?

Maybe I should consider putting it into my current project-a '52 Plymouth Suburban?

[Loren]

I have a 52 Suburban too!

In the coming weeks I might even be able to SEE the car.

It's buried inside a warehouse behind an unassembled garden building I am going to put up soon.

Mine is getting a 265 Chrysler 25 inch engine I built for it.

What a great and useful car!

A recent "Plymouth Bulletin" had Walter Redmond's 52 High-Clearance Suburban on the cover. Kind of gets you going!

One question, have you found a source for the tail gate rubber?

 

I totally agree on V8s (of any kind) in early cars. There has to be a story or some kind of history to make it worthwhile.

Just cramming a V8 in doesn't have enough "romance" for me. I used to live in Northern Nevada where Hot August Nights is a yearly event and after you've seen row after row of nice cars all with Chevy V8 power you begin to think the owners lack imagination. I don't wish to offend anyone, we are all entitled to what gets our pulse quickened. I favor the traditional hot rodded 6 (or flathead V8) that was buzzing around when I was a kid. Chevy Overhead Valve V8s came on the scene too late for me to get excited about, besides when they did start to race they blew up a lot (then). On my Suburban I figure most folks will see that Chrysler Flathead 6 and think it's a Plymouth engine anyway which will be my own little joke. Besides the guys who know what it is are the kind of guys I want to talk to.

[blucarsdn]

Loren,  I can relate to your comment about original type engines compared to OHV V8's.

My 39 Plym conv cpe was a big challenge from the start. After having sat in an open field in Montana for 38 years it was in need of a lot of help to get it back on the road. When I joined the POC shortly after getting the car home in '95 I found out that there were only thirty-five known surviving  '39 convertibles.

The original engine/trans was sitting in the waist high grass surrounding the car when I found it, I left it sitting there. After years of beating across the un-emproved Montana roads, the frame was broken in several places as was the front cross-member and A-arms. Fortunately all of the convertible components were still in the car, as were the chrome trimmed window frames, banjo steering wheel. After a complete survey of the car it was apearent that the car needed a complete rebuild, therefore I decided to do the car as a Rest-o-mod...  Talking to the few Chrysler guys I knew, the prevailing thoughts i got from them was that the car needed a Hemi engine to make it right.

Moving forward, I have a '48 Dodge 4 dr that has a '48 DeSoto Spitfire engine in it. The car was a barn find that was a very nice car, except no engine/trans. Through a trade I had bought a '48 DeSoto that was a rust bucket, however it had a very nice running 25" Spitfire engine and Fluid drive trans. I knew that the Dodges were sold in Canada and other parts of the world with the 25" Spitfire engines, looking at my '48 Dodge I noted that the frame was drilled at the factory for the 25" engine. Wm.

[Los_Control]

I am going to agree with the "tired of seeing row after row of cars with a sbc in it."

Kinda like flat black cars with red wheels .... been overdone so many times it just gets boring.

 

On the other hand, at one time it was cool. My brother inlaw had a 36 Ferd coupe with a sbc, his daddy built in in the 1960's ... back then it was cool.

The typical Hot Rodder did not have a lot of $$ to spend. The sbc was cheap & everywhere. There was a good reason for it.

With todays builders spending $30k-$60k+ on their cars, they can pick & choose engines. I think the sbc is dead reliable and parts everywhere for them ... lack of creativity.

 

I wonder if we are at the end of the road with the sbc conversions? Going to borrow this thinking from Halfasscustoms, not sure if any watch His videos.

He builds several cars a year. He is sticking LS engines in almost everything ... including his wife 47 Dodge truck.

His thinking is, he has a dozen or more sbc out back in the shed he could build & run. But it will cost him more to rebuild the sbc then to slap in a used ls motor that is available and cheap. In true Hot Rodder fashion I understand it .... The guy is building cars for fun.

I am not saying I like this. I am thinking our kids are going to go to car shows and see rows & rows of cars with LS motors in them. Then seeing a car with a sbc and think it is cool.

 

Lets face it we are a dying breed. I am not against motor swaps on our old cars.  Whatever it takes to keep them away from the scrap yard.