48 plymouth coupe/ 68 polara donor?

[DJ194950]

Somethings out of whack here?

 

My 50 4dr. with stock changed to 230 ci.motor,  stock intake,carb,exhaust with an Mopar R-10, pulls easy to +75mph, more if wanting to push the limits of stock braking.

Good grades do require kicking out the R-10 overdrive gear.

 

??

 

Best,

 

Doug

[Young Ed]

I've got a stock 218 and OD in my 48 coupe with a 3.73. While I've only got a couple 100 miles on it since the OD it seems to cruise easily at 70 and feels like there is plenty more. I did 120 miles and only ran into trouble on 1 hill.

[Don Coatney]

Somethings out of whack here?

 

My 50 4dr. with stock changed to 230 ci.motor,  stock intake,carb,exhaust with an Mopar R-10, pulls easy to +75mph, more if wanting to push the limits of stock braking.

Good grades do require kicking out the R-10 overdrive gear.

 

??

 

Best,

 

Doug

What is out of whack? You did not mention what your differential ratio is?

[james curl]

Most overdrive's have a .70 overdrive ratio, to find out the finial drive ratio you multiply the existing rear end ratio you plan on using by .70 to determine the finial drive ratio.  Then using this formula you can determine the RPM's the engine will be turning at any given speed.  (mph x gear ratio x 336 divided by tire diameter).  Example 70 mph times (3.55:1 rear end ratio times .70 overdrive ratio yielding a driven ratio of 2.485:1x 336=58447.2 divided by your tire diameter which should be in the 26" to 27" range would give 2247.96 with a 26" diameter tire or 2164.7 rpm for the 27" diameter tire.  This should be in the max torque range for the mo par flat head engines.

Edited December 15, 2013 by james curl

[Plymouthy Adams]

actually in that scenario you are 900 rpm overshoot on max torque...though the torque is father flat for a few rpm it will fall off a bit...thus the need for the HP that comes in with the higher RPM as peak HP is at 3600..OD of todays cars are geared to be running the highway at 70 MPH at 200rpm less than max torque...so the slight grades and overpasses will not require a kickdown for the 200 rpm rise to max torque will overcome the resistance ...the older flathead just is not deisgned for a a very high rear gear even in OD situations...the factory install of an OD got a 4.1 rear gear just for this reason..I have never seen the torque curve of the Mopar flat six..only the specs if max torque at 1200RPM and the peak HP rating at 3600..example below is a 3.7 V6 Powertec Dodge..notice where peak torque is at lowest rpm...and its relationship to output HP

 

200 ft lb @ 1200 and 100 hp
212 ft lb @ 2000 and 120 hp
220 ft lb @ 2400 and 120 hp
218 ft lb @ 2800 and 118 hp
210 ft lb @ 3200 and 138 hp
235 ft lb @ 3600 and 140 hp
235 ft lb @ 4000 and 178 hp
225 ft lb @ 4400 and 186 hp
222 ft lb @ 4800 and 208 hp
216 ft lb @ 5200 and 210 hp

[wayfarer]

^{My plans are to use the whole drivetrain front to back that's why I am wondering about transmission, my original question was just about rear end widths so I could try to pick up a car that I could use everything from}

 

^thanks

There are a multitude of possible donors...just about everything in to the late 80's has something to offer. Obviously, the engine/trans will be largely unchanged and the axles will vary in width and gear ratio depending on application.

The '66 you last mention could have one of several engines: slant six;  318A (also called 318Poly) or 383B.

95% chance it is a 318 and they are most excellent engines. Not quite as compact as the 67 and newer 318LA but a stout performer none-the-less.

If you need one car to supply the majority of the parts you need then the 66 B-body is a good candidate.

[TodFitch]

. . . .I have never seen the torque curve of the Mopar flat six..only the specs if max torque at 1200RPM and the peak HP rating at 3600.. . . .

Some years ago there was a member on this forum who posted a torque and bhp vs RPM curve for a early 50s (I think) engine. Apparently his father was an engineer with Chrysler and it happened to be one his father kept.

 

But I can't find it in the forum using the search function. That is the type of thing I would have saved off the forum, but I can't find it on my computer nor where I usually keep print outs of that type.

 

Does anyone else remember that?

[DJ194950]

What is out of whack? You did not mention what your differential ratio is?

 Currently 3.9 stocker. Feels like a taller gear will also work as I have plenty of power still avail.

Plan to try a 3.73 as soon as my friend removes one from his 49 Ply. bus. cpe. It's free, but I have to wait for him to get started on that project. He has many. Too many,maybe, but a nice problem to have.

 

Doug

[Don Coatney]

So is it in whack now?

[Plymouthy Adams]

_{Tod...was that by chance Tim Kingsbury?..you may remember his name...if not maybe Don will chime in here..with a name you may be able to find that file...I know I would like to view it and place in my personal folder here at home..}

[DJ194950]

So is it in whack now?

Was referring to James post about the 235chebby motor not pulling 70mph. with the 3.9 rear and his OD trans.

Without trying to start anything-chebby vs mopar, just a question.

 

Ok?

 

Don?

 

I'll drop it OK?

 

Doug

[Don Coatney]

OK

[Don Coatney]

_{Tod...was that by chance Tim Kingsbury?..you may remember his name...if not maybe Don will chime in here..with a name you may be able to find that file...I know I would like to view it and place in my personal folder here at home..}

Probably was Kingsbury. Might be on the discs from the old forum. I will check when I get a chance. First I have to locate the discs.

[TodFitch]

Probably was Kingsbury. Might be on the discs from the old forum. I will check when I get a chance. First I have to locate the discs.

Could well be. Doesn't help on my search though, only thing is a post from 2008 mentioning him posting some years earlier.

 

I did not make copies of the original forum so I hope you can find them.

[Don Coatney]

Remember the days when the forum was re-freshed after 1000 postings? The disc I have has 44 re-freshes on it and that equals 44,000 postings give or take. I first searched for Kingsbury and found him on #12 and he was gone by #15. I then searched using keyword "torque? and found the following. The requested charts are discussed but I never found them posted.

 

Messages In This Thread

More questions for Tim Kingsbury Tod Fitch 9/11/02/ 14:55pst

Re: More questions for Tim Kingsbury Al Bosley 9/11/02/ 16:29pst

Re: More questions for Tim Kingsbury Tod Fitch 9/11/02/ 16:57pst

Re: More questions for Tim Kingsbury tim kingsbury 9/11/02/ 19:23pst

Me too... gtk 9/11/02/ 20:26pst

Re: Me too... tim kingsbury 9/11/02/ 21:24pst

No, pls send me a copy.... *NoTx* gtk 9/12/02/ 00:11pst

Re: More questions for Tim Kingsbury tim kingsbury 9/11/02/ 19:18pst

Re: More questions for Tim Kingsbury tim kingsbury 9/11/02/ 19:54pst

Re: More questions for Tim Kingsbury phill 9/12/02/ 03:30pst

Re: More questions for Tim Kingsbury denise libby 9/11/02/ 20:50pst

Re: More questions for Tim Kingsbury Christopher 9/11/02/ 22:47pst

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More questions for Tim Kingsbury

Posted By: Tod Fitch

Date: 9/11/02/ 14:55pst

If you talk with die hard Ford people you hear that the L-head Plymouths had problems

"throwing rods". Given the full pressure feed to all bearings and the use of modern style thin

shell bearing inserts on all engines built after 1933, I have discounted these tales as simply

spurious allegations by the other crowd.

Based on your posts, it seems it would be possible to suffer rod bearing failure on the

Plymouth L-head 6 if it were run at high RPM. However the 5000 RPM limit you mention

seems much higher than the typical family sedan would ever see. For example, my 1933 PD

has a 4.375:1 rear end and 17 inch tires with about a 28.11 inch mounted tire diameter. 5000

RPM works out to about the following:

1st Gear: 34 MPH

2nd Gear: 62 MPH

3rd (direct) Gear: 96 MPH

I have done some calculations (based on a generic HP curve and typical Cd values for cars

of the era, etc.) that tell me that you will not have enough power on this car to exceed 80

MPH in high gear. So if high RPM oiling problems were an issue it would seem the end

customer would not have been able to get into trouble in high gear. However it might be

possible to exceed 5000 RPM and thus have problems in 1st or 2nd.

So, after all that rambling here are some questions:

1) Is there any real evidence (field service reports, etc.) that shows that Plymouths were

prone to throw rods?

2) If so, was this due to oil delivery problems or some other issue?

3) Wouldn't an oil delivery problem also manifest itself on the pressure gauge? That is, as

long as my pressure gauge shows 40 psi can I be sure am I running in a regime where I do

not have a problem?

4) Does your father have any torque or horsepower curves for the L-6 engines?

5) For long engine life, what does your father recommend for a maximum sustained RPM

on the L-6 engine?

I really appreciate the store of knowledge you bring to the table and your willingness to

share it with us. Thanks!

Plymouth: The First Decade

More questions for Tim Kingsbury

http://merc583.

 

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Re: More questions for Tim Kingsbury

Posted By: tim kingsbury <hitek@webpoint.net>

Date: 9/11/02/ 19:54pst

In Response To: More questions for Tim Kingsbury (Tod Fitch)

Forgot to keep reading..

First off you can't get a stock flathead to get anything near 5000 rpm. You have to do lots of

work from intake to cams to a lot of things so the average person who never touches an

engine doesn't ever get concerned.

You will laugh we have a 1952 Fargo 4 ton with a 265, dual carbs that will turn just around

5200. Top end 70 miles an hour.. It is all tranny and rear end. I also have a 1939 Plymouth

that has a 265, a 5 speed tranny that came out of a 4 ton truck and Dad was in mismatching

gears in the rear end.. It has a bit of a howl but it will legit do 140 mph

and there has been more than one guy blown away with his

vintage ford or chev.. When they see under the hood they stare in disbelieve. Now that 265

is no longer 265.. it was bored out 60, has the lumpiest cam Dad could cut and still keep it

running and has a bag full of Dad's handiwork in it.

But in the 50's stock car boys routinely ran the L heads in excess of 5000 and many were up

in the 6 and 7000 rpm range.

The 8000 rpm engine I refer to is an living experiment where Dad was determined to build a

6 that could blow away a 327 v8 chev on a dyno. the 327 chev was created by a chev

engineer who bitched about Dad an a 340 he built. At the end of the day it wasn't even close

and a 195-something flat head was spinning at 8000 rpm and the 327 chev that was also

punched out pretty far, blew up on the dyno at and I just forget.. 7100 rpm or something...

That engine still exists in Dad's shop as well... I call it the "cross flow ventilation model"

because it has a rod hanging out the side of the engine..

Don't know I can ask Dad, but rod tossing is something I have never heard him talk about in

reference to stock flat head sixes.

2) If there was it was likely caused by a Chev man pulling the oil plug out of the pan of the

Dodge when the owner wasn't looking (we find Ford guys typically didn't resort to this) tee

hee

3) Stock engine or pretty mild.. 40 psi oil pressure.. life is great. But as in Dad's comments I

posted, oil pressure alone is not the true evidence that all is well as RPM's climb. Aka Chev

engineers saw 10psi at one end of the engine and 80 at the other.. But this is racing stuff..

Again 99.9% of the world is so far under 5000 rpm and if you have 40 psi oil pressure,

decent oil and a filter.. life is great.. drive on drive on.

Re: More questions for Tim Kingsbury

http://merc583.addr.com/cgi-bin/webbbs_arch/webbbs_config.pl?read=4665 (1 of 2) [9/26/2002 11:15:23 AM]

4) torque/horespower/rpm curves... drawers of them and drawers of them.. different size

blocks, strokes, bores, carbs, intakes, cams. man the combo's would blow your mind.

Generally it is RPM/Horespower curves that he puddles with.

What are you looking for ? Maybe I can dig around and find something.. But what I know

he doesn't have is anything for the US smaller blocks. Almost all his stuff I think is

Canadian block stuff. Doesn;t mean he doesn't have some US stuff, but it will be internal

stuff if he has it, it will not be on testing he was involved with.

No offense.. but I can't wait to ask him this question..

5) For long engine life, what does your father recommend for a maximum sustained RPM

on the L-6 engine?

We will either get the tell me the year and engine and I will look up the Chrysler Specs.. By

the way they will be in the operating or shop manual I expect for the year and model of your

car/engine.. or I am not sure.. You have to remember, my Dad was always - push the edge

and get power so maximum sustained RPM and Long Engine Life are two things I have

never heard him say in the same sentence.. I will ask him tomorrow at breakfast. We are

hooking up in town and heading out to look at a vintage Dodge stock car

for sale..

[fstfish66]

There are a multitude of possible donors...just about everything in to the late 80's has something to offer. Obviously, the engine/trans will be largely unchanged and the axles will vary in width and gear ratio depending on application.

The '66 you last mention could have one of several engines: slant six;  318A (also called 318Poly) or 383B.

95% chance it is a 318 and they are most excellent engines. Not quite as compact as the 67 and newer 318LA but a stout performer none-the-less.

If you need one car to supply the majority of the parts you need then the 66 B-body is a good candidate.

could also be a  361c,i looks just like  a 383

[dndrodshop]

Used a 8-3/4" out of an E-Body on each of my P15's with '60's 6" wide wheels.

[Old Ray]

Used a 8-3/4" out of an E-Body on each of my P15's with '60's 6" wide wheels.

 

1970 to 1974 Challenger, Barracuda, Duster.  

Wouldn’t most of these be restored cars or used as parts cars already,……… somewhat valuable and hard to find a complete car for a for a donor differential ?

 

Swap meets in larger cities I guess.  

[Young Ed]

1970 to 1974 Challenger, Barracuda, Duster.  

Wouldn’t most of these be restored cars or used as parts cars already,……… somewhat valuable and hard to find a complete car for a for a donor differential ?

 

Swap meets in larger cities I guess.  

 

The most hi performance ones get nut and bolt restorations. The lower end models tend to get upgraded to bigger engines and stronger diffs. Thats your source.

[Plymouthy Adams]

there is absolutely no need to look for a 8 3/4 differential unless you building a monster engine and intend to be ripping up the pavement. ...there are many available axles at a less cost than the infamous 8 3/4...granted if name dropping the 8 3/4 is a good one to throw out...but look closer to home, your intended use of the build, then make your call as to what axle to use.   Buy an axle suitable for your build at a fair price and extend your buying power with the saved money.

[fstfish66]

1970 to 1974 Challenger, Barracuda, Duster.  

Wouldn’t most of these be restored cars or used as parts cars already,……… somewhat valuable and hard to find a complete car for a for a donor differential ?

 

Swap meets in larger cities I guess.  

duster is not part of the  high dollar E body class, its from the low budget A body class along with  dart,demon,valiant,early barracuda and  is narrower then the B and  E class

[Old Ray]

duster is not part of the  high dollar E body class, its from the low budget A body class

 

 

………………………well excuse me,  ……………but you are shooting the wrong messenger, ......that was from information taken directly off a list on the internet (?).  

I now have Ed Hennessy’s more complete / accurate listing so I should be good to go.

 

 

Just a personal observation, and with all due respect to any living perpetrators, but I find Chryslers letter designations, .......and there inconsistencies, ...........very confusing.         

[fstfish66]

 

 

………………………well excuse me,  ……………but you are shooting the wrong messenger, ......that was from information taken directly off a list on the internet (?).  

I now have Ed Hennessy’s more complete / accurate listing so I should be good to go.

 

 

Just a personal observation, and with all due respect to any living perpetrators, but I find Chryslers letter designations, .......and there inconsistencies, ...........very confusing.         

i ment no harm was just  trying to  keep any  one from  being confused about  a duster being an  E body,,,the axel  widths would be  differnt,,,sorry  if  it came out  incorrectly,,,

[Old Ray]

i ment no harm was just  trying to  keep any  one from  being confused about  a duster being an  E body,,,the axel  widths would be  differnt,,,sorry  if  it came out  incorrectly,,,

 

No. it’s just me being over sensitive ………........and frustrated trying very hard to understand the product.

 

I have been playing with cars for 50 years and for the most part, a Mustang or a Camaro is just that, sure they have year model modifications and use engineering / production codes but not changing body types willy-nilly.

 

From the net :

Good trivia question for your buddies. Which one car/model or moniker if you prefer was in A, B, and C body.

A-body. • 63-76 Dart

B-body. • 62 Dart

C-Body. • 60-61 Dart

 

 

So rather the accuse the corporation of being totally dysfunctional I will go with my original theory, …..bad drugs,……. really bad drugs!

[fstfish66]

GM  also  uses  the  letter coding,,,but  i try not to  knwo any thing  about there  stuff,,,,lol