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replacement engine choices for a 37 plymouth?


pyrodork

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i've got a '37 plymouth sedan with a stock (but non-original) 23" flathead that i ruined a couple years ago. i've had a constant struggle since then deciding what i should do for a replacement.

 

option 1)
the guy who sold me the car has a small block 360 from a late 60's dodge truck that he was going to put in it. he says it has j-heads, but i don't know how to externally tell the difference. it needs the typical tuneup parts, as well as an alternator, fuel pump, headers/manifolds, crank pulley, and a carb (comes with a 2bbl and a 4bbl offy intake, and i already have a 4bbl carb that needs rebuilding). the motor does turn and he's got the original motor mounts. he wants $300; but is willing to let me work it off. he has already given me the original-mating 4spd NB435 tranny, an additional NB435 tranny, and a '73 challenger rear end (7:28? it's tagged 2.76) free of charge. the rear end does need all the brake components. he says he chose that particular setup because it wouldn't take much modification to make it work; i.e. still use the stock front end, radiator, driveshaft, little to no steering box issues. he has even offered to help me put it in out of the goodness of his heart.

 

in my research in this forum over the past several hours, i've seen a few mentions of 318s and a couple folks who actually did it. one post has jonnyz72 who says the original front end, rear end, and radiator were still used with his 318 for daily driver use. if i went the 360 route, i would eventually want to put discs in the front. i'm still unclear if the radiator would be sufficient. i know a 12v conversion would be necessary, but i'm not worried about that. pictures or videos of the work of this conversion would be great.

option 2)
i've recently found a '46 fargo dodge truck engine (25"). this engine also turns and appears in decent shape. there has been confusion whether it's a 238 or a 218... i'm inclined towards a 218 because i've never heard of a 238. the owner is willing to work out a trade with me for some stuff i don't need anymore. there is a bellhousing, but no transmission. i've heard that all one would need to do is move the mounts on the top of the radiator to push it forward. in a mock radiator setup, this appears to give me the clearance i need for the fan, but also blocks access to the filler cap. i see don coatney has done the conversion quite nicely, but he has a later plymouth that's not so narrow in the nose. whether or not i go with this option, i would also love to see pictures or videos of how people make this mod work.

option 3)
i also found a rusty/stuck engine/trans from a '39-'40 dodge truck... more or less for best offer. i'm not sure what size the block is, but even though it's cheap, i don't have money to throw into a heavy piece of scrap. i already have one in my plymouth.

 

 

actually coming up with a free-turning 23" 218 or 230 that's within my financial means is proving near impossible. this said, i don't have money or space to work on this project at the moment; but warmer weather and fulltime employment would greatly help me out. at this point, i'm just trying to figure out what i can do. if i can come up with a plan and score one of these engines for little or no cash, i would feel a lot more comfortable about where i'm going with this project. i was hardly able to work in the garage at all last summer, so i've got garage fever pretty bad!

 

oh, i suppose i should mention that my goal is to get my car to be a daily driver... if i want it to be. kinda rat roddy, kinda street roddy. i want to go to shows, cruise long distances... just enjoy driving it. and yes, i'd like to be able to go fast if i wanted to, too. i think the 360 would be my preferred route, but if i could get more of a "drop-in" engine, i could drive it while working on the 360. if i'm going to be spending practically just as much time and money with one as i would the other, i'll do the 360. i also have no experience swapping engines, so if 360 guy is willing to help me, i've got that going for me too. i plan on going to the junkyard for most of the parts i need.

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360 is the same physical size as the 318 so what's been done before in several other cars can be repeated. That said, swapping in anything that was not intended to be in there is a exercise in creative thinking and fabrication. Usually there's more $$$ as well as time, attached as well. If a 218-230 is not within the budget, the V8 swap isn't either. That's the reality. Your most cost effective may be to repair what's there. Some specifics on what is damaged in it may help in finding needed parts/pieces to get it up and going again.

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Yes, what Dave said. If you stuck with what's in it now, or a replacement, then put in an overdrive transmission, you would be able to keep up with freeway traffic. However, I find that taking the backroads or small highways is much more enjoyable in my '48 D24 than try to blast down a crowded freeway with all the people in a hurry to get to where they are going. !! I don't have an o.d., but can do 65mph for short distances if I have to get on the freeway for some reason. But an o.d. trans should put you in the 75mph range, if that's really a plus. But really, I think the old cars should be enjoyed more than raced from point "A" to point "B". For a daily driver, find something cheap and expendable.

 

Robert, if for some reason I felt I needed something other than the 230 in my Dodge, (but don't foresee that happening) I've always thought that the Jeep inline six would be the bee's knee's as far as an engine swap...and you'd still have Mopar DNA. I'd like to think that the days of throwing chevy engines at anything and everything is coming to an end...but that's just me. !!!

 

ken.

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360 is the same physical size as the 318 so what's been done before in several other cars can be repeated. That said, swapping in anything that was not intended to be in there is a exercise in creative thinking and fabrication. Usually there's more $$$ as well as time, attached as well. If a 218-230 is not within the budget, the V8 swap isn't either. That's the reality. Your most cost effective may be to repair what's there. Some specifics on what is damaged in it may help in finding needed parts/pieces to get it up and going again.

That's a succinct and true observation in my opinion.  

Anything will cost $,....it's just a matter of "how much".  Going with the 25" engine may require some modest mods and in my opinion may not be worth the effort.  It still won't be fast. To make it a driver at modern highway speeds I'm thinking trans and rearend are your first order of business.  You may not like the free 2.76 rearend as the gear is so tall that it will be like launching in 2nd gear.  However, 65 mph will be a pleasure if the rest of the car is solid at that speed,......read brakes, steering, suspension and tires.  I drove my car with this set up for a while (in Calif) and it was acceptable once up to speed.

Finally if you need a new engine, there are any number of folks across the country who are pulling their stockers to upgrade to a V8.  That will usually include the trans.  I gave mine away so you may even score one for free.  Now you can spend your money on rebuilding the stocker (it's not rocket science) and upgrading some systems and rebuilding others. 

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That's a succinct and true observation in my opinion.  

Anything will cost $,....it's just a matter of "how much".  Going with the 25" engine may require some modest mods and in my opinion may not be worth the effort.  It still won't be fast. To make it a driver at modern highway speeds I'm thinking trans and rearend are your first order of business.  You may not like the free 2.76 rearend as the gear is so tall that it will be like launching in 2nd gear.  However, 65 mph will be a pleasure if the rest of the car is solid at that speed,......read brakes, steering, suspension and tires.  I drove my car with this set up for a while (in Calif) and it was acceptable once up to speed.

Finally if you need a new engine, there are any number of folks across the country who are pulling their stockers to upgrade to a V8.  That will usually include the trans.  I gave mine away so you may even score one for free.  Now you can spend your money on rebuilding the stocker (it's not rocket science) and upgrading some systems and rebuilding others. 

the 2.76 is far from a respectable rear ratio for a flathead engine..and spells disaster if coupled with an OD tranny...UNLESS you punching the input with a V8 mill..I have the 2.76 in one of my rides with the 383/727 combo. 

 

My only suggestion at this time is to read as many of these thread on here and compare them with your intended build.  What do you want out of the car, the style driving you anticipate and go from there.  Once you have an established build in mind...stick with the plan to get it there and not yield to the temptation to go max or wild halfway through the concept...other than a slight height and width at the exhaust manifolds..the difference between a Mopar small block and large block is not that much...no matter the engine choice, you will find lots of mods are required to get to your goal of upgrading...we talking lay out, phasing and welding for mounts, suspension changes and steering upgrades.  If that is what you want then by all means go for it..just keep in mind it usually is a nonreversible path once you make that first cut..

Edited by Plymouthy Adams
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That's a succinct and true observation in my opinion.  

Anything will cost $,....it's just a matter of "how much".  Going with the 25" engine may require some modest mods and in my opinion may not be worth the effort.  It still won't be fast. To make it a driver at modern highway speeds I'm thinking trans and rearend are your first order of business.  You may not like the free 2.76 rearend as the gear is so tall that it will be like launching in 2nd gear.  However, 65 mph will be a pleasure if the rest of the car is solid at that speed,......read brakes, steering, suspension and tires.  I drove my car with this set up for a while (in Calif) and it was acceptable once up to speed.

Finally if you need a new engine, there are any number of folks across the country who are pulling their stockers to upgrade to a V8.  That will usually include the trans.  I gave mine away so you may even score one for free.  Now you can spend your money on rebuilding the stocker (it's not rocket science) and upgrading some systems and rebuilding others. 

What transmission/engine combo where you running with the 2.76 rear?    Im almost done installing my 230,  tremec t5 5speed tranny, and 2.76 rear..  I did the research and figured Id rather have to start in 2nd gear and cruise comfortable in 5th at 65-70mph

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Pyrodork,

Check out: butchescoolstuff.com.

He makles a mopar install kit-motor mts.& trans. mt.  #2185cp for $200- fits your year car and chosen mopar motor.

 

Love 37 Ply's.

 

Doug

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the Tremec I think that most use is .72 OD and at 2.76 final drive in 5th gear is effectively running 1.98 rear gear..to high..even Chrysler in the 5th Avenues ran 2.32 final drive with the 318...some of the Tremecs can be low as .63 on OD (Mustang) and up to .86 on others.  Your gear tag will tell the story..

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What transmission/engine combo where you running with the 2.76 rear?    Im almost done installing my 230,  tremec t5 5speed tranny, and 2.76 rear..  I did the research and figured Id rather have to start in 2nd gear and cruise comfortable in 5th at 65-70mph

With a 2.76/1 rear gear you will not be able to start off in 2nd gear. You will have to slip the clutch a lot to take off in 1st gear.

 

If you are running 27" tires with a 2.76 rear gear at 70 MPH in overdrive your engine will be spinning 1680 RPM's. I don't think you will be able to go over an overpass hill without downshifting as the RPM's are way below the ideal power range.

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Pyrodork,

Check out: butchescoolstuff.com.

He makles a mopar install kit-motor mts.& trans. mt.  #2185cp for $200- fits your year car and chosen mopar motor.

 

Love 37 Ply's.

 

Doug

i looked at that last night. since this 360 already has the motor mounts with it, i think it would be more of a matter of welding those in and not spending $200 for what looks (essentially) like just new motor mounts and instructions. the ad doesn't really say what all is included for $200.

my current engine threw a rod (see photo) and gashed up one of the cylinders real good. one piston shattered and one has a bunch of nicks in the top. i think the rod may have damaged the block a bit when it was thrown, too. the engine is one of those rebuilt ones with the serial number shaved off, but it's got a tag that says 218. i figured since i want more power anyway, and to drive long distances on the freeway, the 360 might be my best route... but a drop-in would get me on the road quicker. i'm guessing to fix the block would at least run me about $1000... and i'd rather not do that. plus, i'd have to throw new parts in it... then pay someone to make sure it's installed right.

if i did use the 360 and drove it like i should drive a stock engine, i could get away with the current front suspension and radiator for awhile, right? after seeing bob's slant 6 mod on the link he provided, i think it would work until i could get a new front end. are there any detailed pictures/videos of a 318/360 conversion? i haven't checked with the HAMBurgers yet. i think one of the local custom car clubs (frankensteiners) would be willing to give me a hand, too, once i develop a bigger rapport with them. and, like i said, the guy who sold me the car said he would help me install it.

oh, and i would like to keep a standard transmission in the car. would the NB435 be a good choice (since i already have two of them)? should i look into a different rear end?

post-6690-0-58426000-1392098646_thumb.jpg

Edited by pyrodork
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NB435? or do you have a NP435? The NP435 is a truck trans and not really suited for car use.

 

The absolute easiest and cheapest manual OD for the Mopar small block is the AX15. NO adapters, NO special anything for the trans to engine.  Getting it all to function properly in your can will require some dedication and fabrication. If you just bought your first welding machine then you really have a long row to hoe.

 

You might want to cultivate a relationship with someone who has done a similar swap so you have an example (either good or bad) to look at.

 

Don't forget, you will also need to swap the rear axle. Explorers and Cherokees are the best units but others also work.

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I've got to admit, although I've always thought the Jeep six would be the bee's knee's, as I have a Jeep and love that engine, that the slant six might be more better. Pure Mopar DNA and lots of hop-up potential.

 

However, as long as there is an engine in the car that can be repaired, or you can find another like it, I think that's really the way to go, all things considered. That's certainly the cheap and cost effective way to go. You can probably get it on the road, and find a cheap second car for a daily driver at what it will cost to drop in a 318/360, and get it all running right and reliable. Ooops. Now I see you have a motorcycle and a daily driver....so....let's throw out the daily driver idea right now!!! :)

 

To re-iterate a bit, the flathead six can go any distance that any other engine can, maybe not quite as fast. Sometimes I drive Lumpy all day. But again, in these old cars, the journey is more important than how fast you can get somewhere. If I have to get somewhere fast, I hop on a motorcycle, or take my '72 Dart, or, BORING, take the Jeep or the Honda or the pick-em-up-truck. For long drives, are there not alternative highways to take, instead of the freeway, or are you in the middle of the city?

 

Last and probably least, I think a 1937 would be much more enjoyable if it's NOT a daily driver. I think it will lose it's "charm" if you will, if it becomes a work horse, just to argue one more time against that.

 

I like the rat-roddy, street-roddy thing, that's kind of where my car is at....with a flathead six. Lumpy Lou is mechanically sweet, but has no interior to speak of, old carpets on the floor, and she wears primer. But the body is straight, and she has nice chrome wheels. So....??

 

Hope that wasn't too redundant. Once again....too much coffee.

 

ken.

Edited by Lumpy
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Save that connecting rod.  It make a neat "hard luck" trophy  :lol: 

that's why i still have it!

i'm also saving a dented/rusted fender (once i get the darn thing off) to remind me of how awful the combination of pink primer and black paint looked when i bought the car.

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NB435? or do you have a NP435? The NP435 is a truck trans and not really suited for car use.

according to my google-ing of the casting numbers on both of them, they're NB435. i don't have any photos to verify the numbers offhand. i rent my garage, so i can't just run out and look... but that makes me realize that i should have photos of them!

why wouldn't it be suitable for cars?

what trannys would be good, and what vehicles are they found on?

 

The absolute easiest and cheapest manual OD for the Mopar small block is the AX15.

what vehicles have this? is this something i could add after i get it driveable? ...from a financial standpoint?

 

Don't forget, you will also need to swap the rear axle. Explorers and Cherokees are the best units but others also work.

what years? would the challenger rear end that i already have be sufficient?

what about harvesting a front end from a junkyard?

i think i'm fairly settled on the 360... unless a super super cheap and decent 23-incher comes along. i could get the 25"... but it sounds like it would be almost as much hassle with that as it would be with the 360. plus, with the 360, i wouldn't be so concerned about spending a ton of money on speed parts for the flathead to gain just a few horses.

Edited by pyrodork
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Your Challenger rear should be good with your 360 setup, check for width just to make sure.

95 and up Explorers have disc brakes. I have a 98 Cherokee XJ rear that should be a

good fit for my 37, no matter what engine I install.

I put a 95 Ranger rear in my 38, but had to add spacers to get a good width....

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you stated a 7.28  E body  rear end, i dont know for sure if the E body  ever came with the 7 1/4 rear, if it did  internal  parts are hard to come by, except  axel   bearings and seals,and brakes,, internal  repair pasts are hard to find last  time i had any experience with those and are not a desireable rear end for performance, they only came in slant  6 cars and  low performance 273/318  CI  cars,,,  a 8 3/4  or  8 1/4 would be a better choice,   or the  ford  8.8 which are more plentyful and cheaper to  purchase over the mopar  8 3/4 units,, the 360   heads you asked about  will have  a  "J" stamped on the head near the spark  plug  holes,  there were  2 styles of   J  heads small and big  valve, the small valve will be 1.88 / 1.60 the big valves will be 2.02/1.60,,,eitheer head will perform well on a stock 360,good motor  lots of torque and they love a high lift cam,,stump puller motor  long  stroke much like a 440   good luck  hope this helped  a little

Edited by fstfish66
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