'48 Plymouth flathead ?s

[ThriftyT]

I'm buying a '48 Plymouth coupe.   I believe the engine would be the original. Guessing 217?

  My question is I have every intention of splitting the exhaust and adding 2 or 3, two bolt carbs.   What are my options?  It looks like / I'd like to run the dual 2 bolt offenhauser and reds headers.   Does this work?   Bare with me, I have a couple more.    Can I use the edgy aluminum head?    Is it a 23" or 25"?     Thanks in advance fellas.   Can't wait to get this cruiser.  

[ThriftyT]

Or should I build a 230 with all the trimmings?

 

[Andydodge]

Gidday from Oz..........these guys know their stuff...........I was building a 230 with an Edgy head, twin carb Offy intake, Langdon HEI, split Plymouth cast iron manifolds, 1/2 race Waggott cam and a few other bits.........didn't end up finishing it but have attached a pic, Edgy does finned heads for both the 23 and 25" engines, the 23" Plymouth/Dodge engine is 201, 217 and 230 cubes....the 25" Desoto/Chrysler is 218, 228, 250(1) and 265........welcome from oz........andyd  

[Andydodge]

To me the best would be as late a 230 as possible, ie, from a late 50's 230 Plymouth they had 8:1 compression and 140hp, but any improvements for my way of thinking must help........here in Oz the 25" engine is much more common than the 23", but as the 41 Plymouth I was going to install the engine in was factory RHD the extra length of the 25" would have created more problems than I was prepared to worry about......it would have been doable, but as the original engine was a 23" anyway the 230 was gunna be a straight bolt in and as the 230 engine I picked up was an ex airport tug engine with NO engine number its swapping with the original 201 would have been a simple job, a set of number stamps and away I would have gone.............lol...........but sold the car........oh well.......but if you do a search on this forum you'll find Don Coatney has posted a heap of info and details of how he installed a 25" Desoto engine in his 48 Plymouth..........its very straight forward when its a LHD arrangement...............but either way its fun....regards, andyd   

[ThriftyT]

Thanks Andy!    Got any info how you split your manifold?

[Andydodge]

Because the car was a factory RHD car it had something the US LHD cars don't have between the oil and fuel pumps.........a RHD steering box which meant that the Fenton headers would not fit as the front one dumped where the steering box lived...........consequently I had to find an alternative............I found that there were at least 3 different exhaust manifolds used by Plymouth 23" engines depending on various years.............one with the outlet between # 2 & 3 cylinders, another with the outlet between # 4 & 5 cylinders and a third with the outlet at # 7 cylinder, or where it would be if it existed........lol...........anyway so I got one of each of the first and second manifolds that I mentioned, cut the front and back off them which gave me the 2 separate split manifolds and took them to a local blacksmith( I live in rural Australia where blacksmiths can still be found) and got him to weld the ends up giving me a pair of split manifolds that clear the RHD steering box which accounts for that swept back mocked up exhaust pipe, the steering box lived just in front of that pipe..............hope this helps..............andyd   

[ThriftyT]

Right on.  Thanks! 

[greg g]

You need to know what you have before you figure out what you are going to do with it.  Enginswaps on these cars was pretty common as so many were available and cheaper than rebuilding  if one needed major work.  Your engine number should start with P 15 followed by several other digits.  The number is stamped on a pad cast into the block at the front of the engine above the generator.  Having that info will give you a better starting point for your day dreams.  Rule of thumb a built 218 will run like a stock 230, performance parts will fit both engines assuming we are talking US production. I have a dual single bbl intake, shaved head, on a 56 230 enginein my 46 business coupe and am very satisfied with its performance and reliability.

Lots of threads on this forom regarding these types of modifications.  Spend some time searching key words like split intake/exhaust, cams, performance, high compression, etc. 

[Andydodge]

Greg.............one thing tho' is that I have not seen anyone else on this forum do what I did using 2 different, separate exhaust manifolds..............have you seen this done like I did by anyone else?.........the twin outlet/split exhausts that I've seen on here seem to all be just the attachment, ie, welding of another outlet onto an otherwise unmodified stock exhaust manifold..........anyway just curious if anyone else has done what I did............thanks, Andy Douglas   

[greg g]

Andy, there were available for a while modified chevy small block headers being sold by some one.  Used a pass side with the rear outlet cut off and welded closed for the front three and a drivers side with the front cut and welded same for the rear, so fully separated flow front and rear.  Moose on this forum also welded some up that were separate front and rear and the Fenton cast ones now repopped did he same.  I believe George As he and Rusty hope did ones with the heat riser blocked off to keep the fronts and rears in their own pipe.  Me ,I just went with a heat riser eliminated stock with 2 inch I'd pipe all the way back.

[Andydodge]

Greg, I have seen the modified Small Block Chev tube headers, the Fenton cast iron  and recent repops of these, also those tube ones done by Moose and modified single stock cast iron manifolds but what I meant as had anyone done what I did using TWO different cast iron stock manifolds which cleared the RHD steering box? .......not that it really mattered just curious........lol............andyd

[Desotodav]

21 hours ago, Andydodge said:

Because the car was a factory RHD car it had something the US LHD cars don't have between the oil and fuel pumps.........a RHD steering box which meant that the Fenton headers would not fit as the front one dumped where the steering box lived......... 

I had considered installing a dual carby setup on my truck/s Andy, but had the same concerns as you mention. I am certain that the placement of the steering box and the brake master cylinder on the right side of our Oz vehicles would cause additional clearance issues. It would be nice to see a photo from someone who has done this modification here in Oz to see if it does actually work.

I'll be travelling through your way to Newcastle at about 7am on Wednesday morning. Will beep the horn southbound on the highway to wake you up. 

[greg g]

Since clearing the steering box isn't an issue here, it not a holy crap what do I do now deal.  Nice solve on your part.

[hkestes41]

On 4/27/2017 at 9:12 PM, ThriftyT said:

I'm buying a '48 Plymouth coupe.   I believe the engine would be the original. Guessing 217?

  My question is I have every intention of splitting the exhaust and adding 2 or 3, two bolt carbs.   What are my options?  It looks like / I'd like to run the dual 2 bolt offenhauser and reds headers.   Does this work?   Bare with me, I have a couple more.    Can I use the edgy aluminum head?    Is it a 23" or 25"?     Thanks in advance fellas.   Can't wait to get this cruiser.  

Here was the 57 model 230 in my 48 coupe. There was a very noticeable difference between the 230 (132 HP Stock) and the 218 (95 HP stock) it replaced with all the same parts except the Edgy head that I added when I made the swap. In my opinion, if you can find a 230 do it. It is a simple bolt in swap as long as you have the appropriate flywheel and starter. The intake, carbs, headers, HEI distributor were purchased from Langdon's Stovebolts. The head obviously from Edgy. There are now more options out there for new intakes and / or vintage parts as well. 

Lastly look into some form of overdrive. Either a Borg Warner R10, Chevy T5 etc. It makes a marked difference in the performance on the highway. Was probably the best overall upgrade I made to my coupe.