Best 25” Flathead

[kencombs]

Agree wholeheartedly with the full flow recommendation.  I'm slowly working on my 230 and am considering a mod to install a remote, full flow setup. Just trying to figure a way to install lines that are at least as big as the passage in the block, leading from the pump.   I know they ran from the 30's to 50s without, but I've seen the inside of a lot of by pass engines.  Without exception they were gunky.  some of that is oil improvement, some lack of maintenance but IMHO, a lot of it is due to inadequate filtering and no PCV system.

[Don Coatney]

29 minutes ago, Ajgkirkwood said:

Sorry to the OP for my thoughts causing a stir. A 265 motor is the biggest ci, but might not be the best route unless money isn't an issue. From what I seen, finding replacement connecting rods might be an issue, same as a crank. A 251 is a lot easier I find to get those parts for. Myself though, if your looking for a block, look for ones with the full flow oil filtering, well from everything I reading it's a full flow. A lot of motors had no oil filtering or a bypass set up. These engines I'm sure are fine that way as they were made that way to begin with, but there are some with a bolt on full flow, m 265ci motor has it. The (2) 251 blocks I have apart do not have the mounting location for it .

 

 

 

Just because they have the diamond "boss" for mounting the full flow filter does not mean you can bolt the filter on and be good to go. You must insure there is a plug installed as per the diagram below to block the oil passage and divert it to the filter. 

 

 

 

[HotRodTractor]

1 hour ago, Dodgeb4ya said:

I believe all the K series 2-1/2 tonners with the 265 twin carbs/exhaust came with dual King Seeley Handy governors and the balance tube.

But I think....as time went on the  hot rodders got hold of this truck set up and removed the tube and governors for more street performance.

I knew a 85 year old Dodge truck dealer in eastern Washington I would go see occasionally. He told me some of the over the road drivers of Dodge trucks would remove the governors for higher speeds/ quicker transport times... but sometimes engine damage would occur.

Stationary engines / fire trucks used different types of governors to maintain a steady RPM as on the power wagons with optional augers Etc.

Fire trucks would be the same to run the pumps not needing a high speed limit governor.

 

I don't doubt that many people removed the governors - in fact the King Seeleys on the dual carb motor I posted a picture of miraculously have missing butterflies. lol

[duesenberg1932]

I appreciate all the info guys.  Yeah, basically im really just looking for a block that i can go through and wring as much power as i can out if it, reliably. When were the blocks with full flow oil filters produced? Towards the end of production in the mid 50’s, or did the start earlier?  A 251 wouldn’t be a deal breaker if it’s a bit easier to find.  Do these engines have the room to bore them out?  Just kind of thinking out loud.

Edited April 6, 2019 by duesenberg1932

[Ajgkirkwood]

The 251 and 265 are the same bore. They make stock oversized pistons up to .060". 25" long blocks are all the same in terms of what can fit. A 218 25" block with a 3.375" bore would support 251/265 pistons (3.4375") that are 0.060" oversized. A 242ci motor has the same crank and rods as a 251, but the bore of 218/230. So u can bore the 242 to a 251 and use the 3.4375 pistons and have a stock 251

[55 Fargo]

23 minutes ago, Ajgkirkwood said:

The 251 and 265 are the same bore. They make stock oversized pistons up to .060". 25" long blocks are all the same in terms of what can fit. A 218 25" block with a 3.375" bore would support 251/265 pistons (3.4375") that are 0.060" oversized. A 242ci motor has the same crank and rods as a 251, but the bore of 218/230. So u can bore the 242 to a 251 and use the 3.4375 pistons and have a stock 251

Yes a Lets qualify this a Canadian long blocks with 3 3/8 bore can be bored up to 3 7/16 .060 over no big deal heck it will go another .080 if needed over 3 3/8.

This mix and match of Canadian blocks at Major rebuilders was done all the time. 

BTW your in Canada aint no 25 inch 230 its a 228 3 3/8 bore 4 1/4 stroke..

[Dodgeb4ya]

26 minutes ago, HotRodTractor said:

 

I don't doubt that many people removed the governors - in fact the King Seeleys on the dual carb motor I posted a picture of miraculously have missing butterflies. lol

The butterfly plates are  removed.. reason being to disable the governor operation yet maintain correct throttle linkage geometry and not have to bend the 1/2"/5/16"  vacuum lines.

A couple 3-4 ton trucks I have also are missing both governor plates. Common.?

[timkingsbury]

On 3/29/2019 at 9:51 AM, HotRodTractor said:

Does anyone know if the balance tube and carb speed governors were standard equipment on the factory dual carb setups? They appear to be missing from the one in Don's picture.

 

Well after my 7th note from someone I guess I will wade in.   I have no idea what Don's picture is or what the story line there is, but here   Here is the answer to your question.  Yes,  every single dual carb dual exhaust manifold that came from the factory was equipped with govenors and balance tubes.    You could buy the intake assembly which was the intake and balanced tube, the exhaust maifolds (front or back) as individual assemblies from dealers.   Lots of stock car builders would drop the govenors. If you also drop the balance tube as many do, you will find you loose torque and hp.  You will gain rpm if you are simply removing the balance tube from the truck engine that it came from the factory with.  But and here is the key but,  all of those engines that came equipped with the setup and purpose built cams.  So  you only need to take a cam from a 1952-1953 chrysler and put it into the truck engine to raise the rpm, keeping the torque curve. It actually will develop 8 more hp with nothing more than that cam swap.        Again, I am not talking putting in a custom cam or making any other changes, beyond putting in the period car cam into the truck engine. The dual carb/dual exhaust intakes were all produced in Windsor Ontario Canada, and were available at dealers as parts starting in march 1952.  I clearly cant speak to all dealerships but can say the Wellington Motors in Guelph Ontario Canada could still get you the dual carb setup in june of 1974.  I have a receipt for a complete setup purchased that way.

 

[timkingsbury]

18 hours ago, Ajgkirkwood said:

I dont have much experience on this, but this is only my opinion on what makes sense to me. I know the 265 motor is the biggest one and it's the one to have. However I think personally for a 25" block you would want to find a 218, 230 block or even better a 201 block. My reason for this is the stroke of the crank. The 265 has 4-3/4 stroke, the 251 is 4-1/2. Compared to a piston size of 3.4375, it's very much under square. I think the 201 had a stroke of 3-3/4. It was a 3.375 bore, however if u used a 3.4375 piston (like in a 251 or 265) you be much closer to a "square" engine, more so if you get oversized pistons. This will have less stress as you do highway speeds. With the common upgrades of milling the head (and deck too) dual carb and exhaust, and a regrind cam. It could really wake up and be a hot motor.

 

that being said, anyone have a crank from a 218 or 201 to sell?

Hi -  Well  in the 25 1/2" block engines.. the 201 you maybe referring to was moved from USA production to the Windsor Ontario Canada plant when it opened in 1935 for the 1936 model year.  that engine was produced for 14 months out of that plant.  Among other things you may wish to consider..  The crank has smaller journals, the water jackets, are smaller. the oil galleys are smaller..  It really would be the weakest of all engines ever produced out of the Canadian Plant.    When I say that I am quoting my Grandfather who would be the GM of that engine plant when it opened in 1935, reporting directly to Walter Chrysler (and not the VP of production) and he would still be in charged of the engine plant when the very last 25 1/2" engine rolled out of the plant on Nov 11 1959.  The 230 was 23 1/2" block so not relevant to the big block discussion, beyond the small block has offset rods.    With the 218 and I am assuming your are referring to the Canadian 25 1/2" 218 and not the USA small block 23 1/2" engine that are 217 that are often called 218s.   The next generation block would actually be a changed version of the 228 ci motor which started in Windsor in early 1936. That is often referred to as a generation 2 block.  Definately better than the 201 engine,  but there would be a number of changes to the engine blocks and internal configurations.  Even the 1946 250 ci motor has a different block than would a 250 ci motor made after August 1951.   It would be that later block which has the best water jackets,  best oil circulation, reworking of oil passages and on and on.  By that point you could get a 218, 228 or the  series of 3 7/16" bore which would be the 238,  250 and 265 ci motors.  The difference is the stroke which is accomplished by changing rods, and cranks.    4 1/4" being a 238,  4 1/2" being a 250 and 4 3/4" being a 265.   But there is no question the best ever flathead engines ever built are those generations.

 

Among other things and I could give you a laundry list..     Your talking forged cranks balanced to 1 gram,  forged pistons,  rods, pistons and cranks as an assembly balanced to 1 gram. That never existed with any other flathead engine anywhere in the world.  In fact my Grandfather often said -  I defy anyone to find a more balanced engine in the planet that came out of my plant.

 

So if stroke becomes where you wish to draw your battle line..    best try with the 238, 250 and 265 motors..    

 

But  by 1953 the vast majority of all orders for heavy trucks, commercial vehicles, municipal vehicles, industrial engines, for welders,  water pumps, combines, and on and on were 265s.  One can point ot military orders of 250s and I would suggest the reduction in price was the factor. They didnt want to pay the extra  $.    

 

One last one, of total production of any single motor the 265 was produced in a volume larger than any other single motor configuation  from the Windsor Engine plant.   From 1946 until the end of the flatheads, the Windsor engine plants warranty numbers as a % of production was not only the smallest of any Chrysler engine plant by over 98% but the smallest of any engine plant in North America.     The reason was simple..  Build it better,  balance it better and you will get less back.

 

Tim Kingsbury

 

[timkingsbury]

8 hours ago, Ajgkirkwood said:

I seen this stuff before. I know the rods go with the crank, I should have mentioned that. Again I'm  new to this myself however our motors have crazy high stroke compared tothe bores. That puts a lot of stress on the connecting rod, rings, crank and other moving parts due to how fast the piston is moving compared to the rpm, how much side load there is on the rod and what not from being so far out cause of the stroke. With the 265, it having the longest stroke and all 25 blocks are the same for the most part, it ends up having the shortest connecting rod, so we have a piston moving a lot faster per rpm compared to most engines because in that 1 rpm, it has to travel up and down 4-3/4 vs 3-3/4 that's on the 201. The shortest rod length means that rod is moving at more extreme angles then the 201 crank and rod would cause. Yes the stock 265 vs stock 218, it's the king of torque and horse power.... but by how much? Plus with the upgrades that are commonly done, that helps to equal a lot of things out. In 1954 the 230 was rated at 110hp the 265 was 119, however by 1959 the 230 was rated at 138. This could mean something or could mean nothing. 218, 230, 251 is easier to come by then the 265. 

Well you make some interesting observations.    On HP your numbers are not quite correct and what was published was for the 265 coming out in 1952 under valued and with a purpose.  I have uploaded many times and can send it to you, the 1952 poster which was the start of the 265 and as well the start of dual carbs and factory dual exhaust, but also 241 dodge hemi. The Hemi for what they called the medium tonnage field was primarily municipalities and contractors, dump trucks etc. It w4 ould come out at 133 hp.  The 265 for the truck with the truck cam and dual carbs and dual exhaust was 155hp.  That not a guess, thats a fact. But marketing said if you say that we will never sell the hemi, so we want it cranked back. At one point the poster was the hemi at 133 and the 6 and 132,  but when it hit the dealers in December of 1951 the 6 was tucked into the corner and was shown at 136 hp.  Pure marketting. No difference to the 1964 426 hemi being called 425 hp with a single 4 barrel, and in 1966 with a wilder cam, 2 4 barrels it was still 425 hp. That of course was for insurance purposes.    In any case I digress.

The 265 from the factory with a chrysler car 265 cam in it, was the most hp of the 23 1/2" or 25 1/2" engines.

 

But connecting rods..  You are correct, the shorter the rod the bigger the angle.    Now its the balanced crank, rods and pistons that offset your concerns it really does.

Think about it..   GM, FORD, you name the manufacturer.. Who else had forged cranks balanced to a gram..  answer no one..

 

Back to your point..  Let me just say that in the 238/250/265 series engines, they are all exactly the same bore..  3 7/16"    If your having custom made forged pistons made

well what you do is take a 238 rod, and raise the pin placement on the pistons.        Longer rod and better angle.  It doesnt work with a 218 and a 201 is smaller rods bearings so not relevant. The point being  on that one point your correct.. long the rod the better..  if..  key word if you not negatively effecting displacement.

 

As so many would tell you, there is no replacement for displacement.

 

 

[timkingsbury]

On 3/27/2019 at 9:20 PM, duesenberg1932 said:

Hi everyone,

I’ve been wandering the web looking for information on flathead mopar 6 cylinders, specifically the larger 25” block.  Is there any specific iteration of the 265 that is considered the best as far as durability and making horsepower is concerned?  Im having a bit of a hard time finding specific info on these engines.  Any help or a point in the right direction would be greatly appreciated.

Thanks

Anything with a date after august 1951 is the best blocks made.    A bypass oil filter does a better job of filtering oil,  but a full flow starting in 1954 model years will see all the oil passed through a filter.  You can drill into a by pass block and put on a full flow on it.    Here its done on a 1949 Canadian Plymouth block, which started its life as a 228 and is now 125 thou over bored 265.   You can run both a bypass and a full flow if you like. There are 265s with either configuratons that you can consider as durable as anything ever made.  All of the Canadian engines after ww2 in the 25 1/2" series are all forged cranks, balanced to 1 gram,  forged pistons (from the factory unless ordered by a secondary manufacturer) and balanced assemblies of crank, rods and pistons.

 

You will see lots referring to combines and industrial engines.  You can get into engines that are purpose build, maybe with sodium valves and low rev cams.  Often industrial engines have cams to meet a specific hp configuration but also a per hour fuel consumption number will have a specialty cam.    It is the cam which a lot miss and there are a huge catalogue of cams that were ground for the 25 1/2" engines.

 

The whole topic can be an explosive one and everyone has an opinion. Sadly I find a lot of opinions can be without any experience or expertise behind them.  As I have read your posts you talk durability, but then I see the thread going in the supercharger and other directions.    I will take a slight tangent here to say, that once you move any engine into a turbo or super charger arena,  a cam with a certain number of degrees of separation between when an intake closes and exhausts opens, and visaversa on exhausts closing and intakes opening, become critical if you doing much more than using them as jewelry.  By that I mean if your just putting it on with a tiny boost as many have ok..  In those cases I can get way way more power out of a naturally aspirated engine.   But if your going to start cranking up pressure, you need separation and no stock cam was ever cam with such seperation.

 

We are happy to provide without charge the specs for at least a couple of cams for superchargers or turbo charges.

 

After that,  drop me a note any time..  fargopickupking@yahoo.com   and happy to discuss further.

[9 foot box]

   All of that and more information is in Blogs, at the top of this page. Thanks Tim 

[duesenberg1932]

1 hour ago, timkingsbury said:

Anything with a date after august 1951 is the best blocks made.    A bypass oil filter does a better job of filtering oil,  but a full flow starting in 1954 model years will see all the oil passed through a filter.  You can drill into a by pass block and put on a full flow on it.    Here its done on a 1949 Canadian Plymouth block, which started its life as a 228 and is now 125 thou over bored 265.   You can run both a bypass and a full flow if you like. There are 265s with either configuratons that you can consider as durable as anything ever made.  All of the Canadian engines after ww2 in the 25 1/2" series are all forged cranks, balanced to 1 gram,  forged pistons (from the factory unless ordered by a secondary manufacturer) and balanced assemblies of crank, rods and pistons.

 

You will see lots referring to combines and industrial engines.  You can get into engines that are purpose build, maybe with sodium valves and low rev cams.  Often industrial engines have cams to meet a specific hp configuration but also a per hour fuel consumption number will have a specialty cam.    It is the cam which a lot miss and there are a huge catalogue of cams that were ground for the 25 1/2" engines.

 

The whole topic can be an explosive one and everyone has an opinion. Sadly I find a lot of opinions can be without any experience or expertise behind them.  As I have read your posts you talk durability, but then I see the thread going in the supercharger and other directions.    I will take a slight tangent here to say, that once you move any engine into a turbo or super charger arena,  a cam with a certain number of degrees of separation between when an intake closes and exhausts opens, and visaversa on exhausts closing and intakes opening, become critical if you doing much more than using them as jewelry.  By that I mean if your just putting it on with a tiny boost as many have ok..  In those cases I can get way way more power out of a naturally aspirated engine.   But if your going to start cranking up pressure, you need separation and no stock cam was ever cam with such seperation.

 

We are happy to provide without charge the specs for at least a couple of cams for superchargers or turbo charges.

 

After that,  drop me a note any time..  fargopickupking@yahoo.com   and happy to discuss further.

Thank you kindly.  This was exactly what i was looking for lol.  I have a few ideas on which direction I want to go, but nothing set in stone.  Once i get my hands on a block i’ll have a more concrete plan.   I try not to get to far ahead of myself.  Id like to get to the 200hp mark if at all possible.  I will definitely be in touch.

[40desoto]

6 hours ago, Ajgkirkwood said:

Sorry to the OP for my thoughts causing a stir. A 265 motor is the biggest ci, but might not be the best route unless money isn't an issue. From what I seen, finding replacement connecting rods might be an issue, same as a crank. A 251 is a lot easier I find to get those parts for. Myself though, if your looking for a block, look for ones with the full flow oil filtering, well from everything I reading it's a full flow. A lot of motors had no oil filtering or a bypass set up. These engines I'm sure are fine that way as they were made that way to begin with, but there are some with a bolt on full flow, m 265ci motor has it. The (2) 251 blocks I have apart do not have the mounting location for it .

What I dont like about this setup is that you have to remove the oil filter assembly whenever you need to remove the starter?

[Dodgeb4ya]

Every 25 years both the starter and the oil filter housing should be serviced and or need repair.

Especially the OF housing quad O-Ring.?

[Ajgkirkwood]

1 hour ago, 40desoto said:

What I dont like about this setup is that you have to remove the oil filter assembly whenever you need to remove the starter?

Yup... when I first did oil changes, it had no drain, had a flat spot on the bottom for something to be drilled and tapped though, anyways after a few messy oil changes, well that was fixed

[maok]

3 hours ago, duesenberg1932 said:

Thank you kindly.  This was exactly what i was looking for lol.  I have a few ideas on which direction I want to go, but nothing set in stone.  Once i get my hands on a block i’ll have a more concrete plan.   I try not to get to far ahead of myself.  Id like to get to the 200hp mark if at all possible.  I will definitely be in touch.

 

Why do you want/need 200hp? 

 

EDITED : (Did they not come with L8?)  Oops, it was the Chrysler version that had the L8

 

If you do a basic re-build with some HP mods, it should give you more than enough torque/hp to be a great cruising post vintage automobile.

 

If you need to do highway speeds, I don't know the diff ratios of a '37 Airflow,  but there maybe an overdrive unit available, if not a diff swap maybe something to consider.

Edited April 7, 2019 by maok

[Dodgeb4ya]

I've never worked on or driven the six cylinder Airflows but have done so on the the eight cylinder cars.... C2 Imperial Cpe and a CW limousine...both OD cars.

Never a need for more power in the eight cylinder cars.

323 and 385 ci. eights. Smooth and quiet.

Building a six with a cam, twin carbs and exhaust will probably be some what "truckish" feeling and noisy. Not smooth feeling and quiet.

Modified engines seem to be driven with the pedal down farther and more often.

JMO.

[Don Coatney]

2 hours ago, Ajgkirkwood said:

Yup... when I first did oil changes, it had no drain, had a flat spot on the bottom for something to be drilled and tapped though, anyways after a few messy oil changes, well that was fixed

 

 

I drilled, tapped, and installed a pet cock.

 

[55 Fargo]

6 hours ago, maok said:

 

Why do you want/need 200hp? 

 

EDITED : (Did they not come with L8?)  Oops, it was the Chrysler version that had the L8

 

If you do a basic re-build with some HP mods, it should give you more than enough torque/hp to be a great cruising post vintage automobile.

 

If you need to do highway speeds, I don't know the diff ratios of a '37 Airflow,  but there maybe an overdrive unit available, if not a diff swap maybe something to consider.

200 hp is not a simple matter to attain on these engines including a 265.

Maock notice the OPs handle 32 Duesenberg, just that name invokes huge HP in its time.

Nothing wrong with getting as much power as possible, makes for strong highway and mountain road cruising.

[55 Fargo]

4 hours ago, Don Coatney said:

 

 

I drilled, tapped, and installed a pet cock.

 

Great selling feature....

[40desoto]

Wow!  Last year there was two 1953 Windor’s both with 265 motors in them, I believe $500 for both.

$4500 for this 265 motor. ?

https://www.ebay.com/itm/CHRYSLER-SPITFIRE-265cui-Flathead-6-W-TRANS-SUPER-RARE/192879816030?hash=item2ce8886d5e:g:7NkAAOSwp-FcpQwK

[MarcDeSoto]

I've heard of a Spitfire engine which were in Chryslers, both sixes and straight eights.  But I've never heard of a SpitSFire.  Oh, I see, you painted that on.