Mopar flathead 6 motors- whats to be expected

Many years ago I put a big Chrysler six into a 1950 Dodge (Canadian) and didn't move anything, man that old Dodge would fly!

 

^^^^that's cuz mopar used the same long block for all cars/trucks made there. So just a bolt in for you.

 

The head was $750 plus shipping. Pretty reasonable if you compare it to the price that some of the vintage stuff goes for, especially when you consider the condition of the plug threads and flatness of the old parts. The intake, distributor and headers came from the stovebolt site.

Edgy also is now producing intakes. You can find various intakes on ebay from time to time.

 

OK I've got a flat 6 and trans from a '37 Dodge truck. It's 25". Is this right? And if so what cubes is it? I'm thinking of building a cheap little rod around it.

thanks!

 

i know you said flat motors but there is a guy up in toledo area that runs a slant 6 motor in a late 40s plymouth but he said it took some doing to get it in.

 

Ill give you the one out of mine if I don't trade my truck off and put a different motor in it. 50/50 shot there...

I believe its a 331.

cb1

 

More likely a 241ci or 251ci now that I look at my reference. May have to get a better look at the number on the block..

cb1

 

Lucky man! I heard the PO had rebuilt the carb but man the garage sticks of gas....I wonder what the oil smells like? The block has the usual front and rear leaks so a full gasket set is in order...figure I'll pull the carb and go thru it...maybe I should just pull the head and see what she's doing?!
I'll start soaking the head studs {PB blaster}and in a week or two try and pull it.
Funny thing about cars...sometimes they can get just as much problems from sitting than from constant running, and mine's been sitting!-alot!

 

Welcome aboard! This is why I wanted to start this thread, for all of us flahead folk!
-1st thing you should do is measure from the front of the head to the back...you'll be either just under 23" or 25" -which one you got?
-2nd, read off the block tag above the generator..there's folks here who can decode that. Simple premis is that even though your truck is a 37{nice!}, doesn't easily mean the motor has never been swapped along it's lifetime.

 

Keep in touch with us about that block please...I know that if 73RR doesn't want it, I sure would...watching my feet now so I don't step on anyone's toes!

 

Too far to ship... Have at it.

Here is a link to ID numbers:
http://www.t137.com/registry/help/otherengines/otherengines.php

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I know it's just under 25". I'll have to check the #'s again. Thanks!

 

Here is a cheater for folks trying to determine displacement. There is a pipe plug screwed into the head above #6 Cylinder. Removing it allows you to insert a length of stiff wire in order to determine the stroke as the wire will ride the piston through its stroke. Just don't use the starter, and make sure the wire is at least 7 inches long.

on the later models of 23 inch variety, 4 3/8 = 218, 4 5/8 = 230.

the earlier 198 and 201 motors had 4 3/8 stroke but smaller bore.

Dodges were 201 or 218 through the 1942 model year.

 

I pulled the air cleaner off the other night just to get a good look at it {design} and for some reason I opened the throttle at the carb and saw a sizable pool of either oil or gas down the throat of the carb, in the intake manifold...I think I definately need to pull the side covers and maybe the head and check the valves for full closing. Mind you this could be a bad "high" float adjustment too...

 

I have one of these engines, infact the whole car and have been thinking about a re-do on my 23 Dodge roadster, I'm pretty suire it's a low mileage 251 (engine # C38-95379) with the fluid drive . What I'd like to know is what flywheel/bell housing and clutch combination should I be looking for to eliminate the fluid coupling, and is there a way to adapt a Ford top loader to it. I think dressed up a bit it would look great in the 23 dodge.

 

The Plymouth bellhousings ('normal' 3-speed) are the shortest/shallowest and may work with the Ford trans. Obviously, the bearing register diameter and bolt holes will need some work and a custom pilot bearing will likely be needed but the depth might be close. Others have used the t5 with success and the input lengths are close.
You will need to source a 146 tooth flywheel.

If an OD interests you I can adapt the AX15.
.

 

What transmission does it have??? fluid drive is not the transmission it is the the transfer system between the engine and the transmision. If its the regular 3 speed, fairly likely in a windsor, whats the need for a change. With a light car the fluid drive will not even be noticed. They are about 95% effeicient in transfering power. If a modern trans is what you need check wil cap for thier adapters. I had a ride in a 251 powered A roadster backed up by a GM 350. It had more than sufficient get up and go. Athough I must admit that 65 on a Nebraska dirt road felt more like 90.

 

my friends 30 chrysler needs to be reringed, silver dome, is there any thing special about the rings in these engines? i have yet to pull the head so i'm not sure of the bore, also what about crank bearings and oil pumps are they easy to find, thanks for any help.

 

Thanks, I'll check out the flywheel and adaptors, my only concern with the fluid coupling is it's bulk and weight.

 

pistons are oval ground aluminum alloy with 4 rings. Check Vintage power wagons for parts. 196 or 218 cu inch unless it an imperial. 3 1/8 bore, 4 1/4 or 4 2/4 stroke depending on model. egge also as pistons and so shold terrel machine in texas.

 

George Asche took us for a ride in his Dodge Sedan, '49 or 50 I think and it was an EYE OPENER to say the least. His is a 265 dual carb, cam, split exhaust and compression and a SIX speed stick and it set us back in the seats. Call George for all his specs

 

I've never even considered that adapters for modern 5 and 6 speed transmissions were available. I'll pull the engine and start cleaning it up. I'll be in touch.

 

I found an Edmunds head in a junk yard a couple months ago, and have thought about building an engine under it.
The head sat on the front seat of a Crovair for at least 20 years--it's not all eaten up; water passages are good, combustion chambers look good.
It's for the 218/230.

In my barnstorming quest for a plan, I found some good stuff and had a few ideas.

From what I found, the 218 and 230 used the same pistons: the 230 used a longer stroke crank and made up the difference with shorter rods.
I thought I saw pics of pistons that had 4 rings; someone told me they only had 3, someone here in this post said they had 4.
Generally speaking, a set of forged pistons is usually $100 a slug. That would be in the neighborhood of $600 for a set of forged pistons.
A set of cast pistons is probably about half that, maybe a little more, maybe a little less.
But, if you used forged pistons, you could have modern rings put in it, and you'd only need three of them. There's power to be made with Zero Gap rings (if there's a set available for that bore diameter), and one less ring is less parasitic loss.
More importantly, if you have a set of pistons made, you can move the pin height up to use the longer 218 rods. You could also get rid of a bunch of skirt--the skirts on these pistons are about a yard long... it's like putting a connecting rod in a paper towel tube.
Less piston weight is always good, but a longer rod will give you more piston speed and should make a little more power because it hangs at TDC longer and creates more velocity when drawing the charge in because it runs down the bore quicker from TDC.

It's not more cubes like an offset ground crank would be, but it is a reasonable way to get a little more RPM and the performance of a longer rod.

Though it wouldn't be much of an argument to say that's like wizzing in a lake in an effort to raise its level.

-Brad

 

Here is a link to ID numbers:
http://www.t137.com/registry/help/otherengines/otherengines.php

.[/QUOTE]

I pulled my rear main cap from my 49 Plymouth L6 to replace the rope seal ... no rope - neoprene instead - and it is not attached with 3 bolts from circa 1955. So I am confused - I think somebody did not use the original type. Is a rope seal and neoprene interchangable?

And to the original intent of my post - due to my confusion above I tried to verify my engine. Big P on the head - but NOTHING is stamped on the block on the serial number pad (per link above). Am I missing something?

thanks

 

Some of the old rebuilder used to remove the numbers from the pad below the head when they would rebuild the engine. In it place they would often attach a metal tag with the rebuild specs. Look around for a tag attached to the engine somewhere.

 

One of the guys on the P15-D24 site had Venolia build some custom pistons for his 230 rebuild.

"I had Venolia make some forged pistons for my overbored 230 that were gorgeous. I just sent them a stock piston, a bore diameter, some thoughts on wristpins, and a set of rings that I wanted to use, and was very pleased with the results."

"Pistons shouldn't be a big deal. I looked back through my old records, and found that in September of 1996 Venolia made me a custom set of forged pistons for my 230 with an uncommon size and a metric ring package (a long story) for just $412.51, including shipping"

If you are lucky they may still have the specs for those pistons.

 

And to the original intent of my post - due to my confusion above I tried to verify my engine. Big P on the head - but NOTHING is stamped on the block on the serial number pad (per link above). Am I missing something?

Chrysler sold un numbered blocks to rebuilders. Chysler had a Method that they liscensed to rebuilders that specified only blocks the check out to Standard Bearing specs could be used for these Chrysler method rebuilds. Others like as mentioned usually riveted a tab specifying the over unders used but those many time get knocked of.

So your block is likely an unumbered block that got asembled aftermarket and somebody forgot the stamp in the number part. Alot of states also used engine numbers for registration and titling purposes so these unstamped blocks allowed the rebuilder to stamp in the original number to keep documents matching the vehicle.

The P generaly designates Plymouth but who knows what year.

I believe I read where some one installed Toyota supra pistos after having his block bored to their specs. I believe it has been stated that the blocks can go to .090 over bore and still maintain enough material between cylinders as to not be troublesome.

Do keep in mind that in the short blocks the pairs of cylinders are siamesed and the rods for the pair are offset, and they need to be maintained in thier respective pairs.

Also of some interest is the size and design of the combustion chambers. If you look at a 218, when the piston is a TDC, they sit down about 3/32 in the bore. On the 230, the psiton is nearly flush with the deck of the block. It is said that 218 combustion chambers are smaller in volume than the 230 heads to keep compression ratios reletively the same. Some have mentioned that the 218 heads combined with a 230 block yield a tighter squeeze. I do not know if there is any positive writen confirmation of the differences, but it has been discussed in several places. Also if you look at the spec charts through the years, HP goes up associated with more compression from the 30's through the late 50's. Unfortunately, I did not compare the 46 218 head to the 56 230 head, I just milled the 230 head .040 and had .010 taken off the block.

 

Everything you wanted to know about mopar flat head 6 engine numbers

site also has an embeded serial number lookup for vehicle information

http://www.t137.com/registry/help/otherengines/otherengines.php

 

Also of some interest is the size and design of the combustion chambers. If you look at a 218, when the piston is a TDC, they sit down about 3/32 in the bore. On the 230, the psiton is nearly flush with the deck of the block. It is said that 218 combustion chambers are smaller in volume than the 230 heads to keep compression ratios reletively the same. Some have mentioned that the 218 heads combined with a 230 block yield a tighter squeeze. I do not know if there is any positive writen confirmation of the differences, but it has been discussed in several places. Also if you look at the spec charts through the years, HP goes up associated with more compression from the 30's through the late 50's. Unfortunately, I did not compare the 46 218 head to the 56 230 head, I just milled the 230 head .040 and had .010 taken off the block.[/QUOTE]

Would a mild hop up on a 218 like milling the head .50 and split stock exhaust be a noticeable difference in power?

 

218s went from 87 to 100 Hp at the flywheel with not much more that increased compression from 6.5 through 7.1 So what do you suppose would happen by taking the CR to 8.5 and improving the breathing???