260 poly v8 into a 40's Mopar

[40plyguy]

 I'm sure someones put one of these or an early Hemi into a 40's Mopar. Contemplating pulling the flathead out of my 40 Ply and replacing it with a 260 poly and a 3spd trans Looking for some tips and advise. Thanks much in advance.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

[mrwrstory]

You'll get lotsa input from this group. I sure like your idea.  I have a '40 Sedan and hope to some day install the Poly I am building as a long term and a separate project.  

What Poly do you have?  Could it be a 259 from a Plymouth?  Dodge did a 241, a 270 and a 315.

Where are you located?

[Andydodge]

Welcome from Oz..........I put a 1962 318 poly & cast iron auto in my Oz 1940 Dodge(40 Plymouth based) in 1973 & its still there...........at the time here in Oz it was all I could afford & find, if I did it again I'd use a later poly with the 727 auto as I have had problems over the years with annoying leaks from the auto.......am not familiar with the early poly physical dimensions as they were never sold here in Oz, the 1st polys we got were the 1957 versions........anyway I ended up using a rack & pinion from an Austin 1800 which I had to narrow 9"..........I mounted the engine quite low in the chassis which you can tell by the engine pics.............anyway they fit, just measure twice & cut once......regards, andyd          

[40plyguy]

I'm in Milwaukee, Wi. I haven't  committed to buying the engine and trans yet. It's a 260 from a 1955 Ply. with a 3 speed standard trans. I thought it may be kind of neat and old school. I thought I'd 1st get some feedback as to any issues I might encounter from someone who's done it before. I've been working at freeing up the original flathead and this happened to come along. I did some measuring today and am concerned about the steering being in the way. I didn't want to change that. As a matter of fact i was hoping to keep the shifter on the column. I emailed the seller for dimensions. he said the engine is 24" wide and 56-58" long (I assume he means the eng and trans complete). Compared to the flathead and 3 sp. that's abt 10" longer. The thing that intrigued me is that the engine mounts up front and at the sides pretty much like the flathead setup. 

[dale]

Never heard of a poly engine.. What is it...

[DJ194950]

http://www.allpar.com/mopar/poly.html

A good explanation!

DJ

[DrDoctor]

   The term “poly” is short for polyspherical, which in this case refers to the shape of the combustion chambers within the head. In the early- to mid-50’s, V-8’s were rapidly becoming dominant among the upscale brands, but Chrysler’s Hemi’s complexity made it slow, and expensive, to build, and Chrysler’s costs were far higher than either GM’s and Ford’s. Customers didn’t seem to care about differences in efficiency. Thus, in what appears to have been a fast response to a serious problem, Chrysler created a new, cheaper, lighter, series of engines based on the Hemi. The new series was dubbed the “poly” after the polyspherical head’s rounded, circular combustion chambers. To cut back from two rocker arms to one, they put the intake valves on the top side of the rocker arm, and the exhaust valves on the bottom side. The bottom of the valve covers were scalloped so the spark plugs were accessible from the top — unlike Ford and Chevrolet V-8’s, where owners had to reach under the hot exhaust manifolds to get at the spark plugs. Overall, they were able to lower costs, and weight, while increasing production, making up for reduced efficiency with higher displacement. The poly head engines went by a variety of different names, including “Fire Dome”, “Power Dome”, “Fire Power”, Spitfire”, and “Hyfire”, dependent upon the division. Thx.

[Andydodge]

Polys were the poor mans Hemi.......lol.........says he who has one..........btw the Firedome was the Desoto hemi, FirePower was the Chrysler Hemi ...........and even allowing for the sawtoothed shape of the rocker covers of the 2nd version of the Plymouth Poly in 277/301/313/318 cubes you still give your fingers a nice warm glow changing spark plugs.........Chev Big Blocks and Fords Cleveland engines have a similar valve setup...............andyd

[DrDoctor]

   I feel that I probably went into too much detail about the poly engine here. I also feel that I lost abit of my self-composure earlier this evening in another topic forum, but I’ve not had a good day today, and . . .  well . . .  I think I’ll just shut up, sell my soap box, and just read more, and contribute less.

[Flatie46]

I bought a parts car from a local junkyard that was crushing out about 10yrs ago. It was a 47 Club coupe, someone had put a poly engine in it, they had the 3spd shifter coming up thru the floor. The engine looked like it fit well but I don't think they ever got the project going. Reason being if it would have had the fan on the engine the way they had it mounted it would have been sitting where the radiator support was. Maybe the engine could have been set back further, could have used electric fans on the outside of the radiator or whatever. I didn't really pay much mind to what had been done as I didn't plan on putting a V8 in my 46. I just pulled all I could save from this car and sent it to the scrap yard cause it was so badly rotted. Just saying I had one that had a Poly in it. The way they had it in, it didn't interfere with the factory steering.

[40plyguy]

 I was searching on the HAMB and found a reprint of an old article from a vintage Custom Rodder magazine. They detailed putting a 241 Red Ram Hemi into a 46-48 Plymouth. I'm guessing the Poly engine would be very similar. Getting the engine in and mounted doesn't seem too bad but the steering was kind of a mess. They made tubular headers for the exhaust . Then they cut the steer shaft near the firewall . Added an extension shaft with a u joint on each end and a bearing block mounted to the frame. The new steer shaft ran between the left side header tubes. I 'd be afraid of having an issue with exhaust heat on the steer shaft. Not a fan of that.

[mrwrstory]

Okay "Cheese Head"   welcome!  I'm surprised no one has jumped on the install and steering issue.  

For starters, installing the Poly would be almost an identical install as on the 56 Plymouth.  Additionally understand that Mopar had the steering issue with their first V8s going in cars that were previously 6s.  If the Poly you're considering is still in the car, I'm betting you'd find the engine offset to the passenger side something like 1.5".  I know that was the case with '53 Dodge HEMIs and that was done in production so's the HEMI head/valve cover would clear the stock steering column,....nada problem with the earlier and still optional straight 6.  The offset in production is not apparent unless you put a tape measure on it.  When you acquire the Poly be sure to get as much of the Plymouth mounting hardware as you can.  I'm betting you could use much of it w/o modification, I believe it would account for the offset and would simplify your install.  

Go for it man!!!  No guts no glory!!!  It would be really cool!!!  And, there's lotsa help on this forum,,,,,maybe along with a few snide comments about modifying a stock car.  Keep us posted.

Edited March 20, 2017 by mrwrstory
up dated info

[40plyguy]

And I had just made up my mind to stick with the flatty......You got me wondering if the front engine mount in the article I was reading was fr the flathead and put on the V8. Not sure if that's possible but that may have been part of the problem.  In my way of thinking that would put the engine more centered in the chassis. Is the V* engine centered in it's front mtg brkt and moved over to the right on the front crossmember.? Or is the engine offset to the right in the mounting brkt and bolted in the ctr of the crossmember, if you know what I mean? 

[mrwrstory]

I don't know with certainty that the offset is achieved via the front engine mount but,....it makes sense.  Hopefully someone else will chime in.  The point where the engine mount mates to the frame may be diff, considering that interface to the frame may have changed some between 1940 and 1956.   Addressing that diff. should be a no brainer if you are confident enough to do an engine change.

Good luck.  Keep asking questions.

Edited March 20, 2017 by mrwrstory
up dated info

[wayfarer]

16 hours ago, The Dr's In said:

 The poly head engines went by a variety of different names, including “Fire Dome”, “Power Dome”, “Fire Power”, Spitfire”, and “Hyfire”, dependent upon the division. Thx.

Yeah....not quite young grasshopper......

Fire Dome is a DeSoto Hemi.

Fire Power is the Chrysler Hemi

and what the hell is a Power Dome?

Please don't add mis-information to the www, there is enough already.......

[jhm1mc13]

In 1963 my 1950 Plymouth six expired so I put a 1955 Plymouth V8 in and moved the steering box into the frame for clearance which maintained center.  Maybe a bad idea but it worked for years.

Jim M

[dale]

I guess I know what a poly motor is afterall by those valve covers..  I put one like that in a Plymouth coupe about 50 years ago when I was a young guy.  Had to go around the steering column with the back right exhaust but the original transmission bolted up to the V-8 motor. Flywheel, clutch, and driveshaft  were the same too.   Never had to move the transmission.. Think the radiator worked without moving it.  Put a floor shifter on.  Other than that she fit right in with linkages and fittings etc....  The motor remained on center too..  I remember it as a very easy job as I didnt have a welder or cutting torch.  Torqflight would be nice.

Edited March 20, 2017 by dale
addition

[DrDoctor]

 

   I feel that I probably went into too much detail about the poly engine here. I also feel that I lost abit of my self-composure earlier this evening in another topic forum, but I’ve not had a good day today, and . . .  well . . .  I think I’ll just shut up, sell my soap box, and just read more, and contribute less.

 

   Not quite yet . . .  Here’s my original treatise about the polyspherical engine —

 

   The term “poly” is short for polyspherical, which in this case refers to the shape of the combustion chambers within the head. In the early- to mid-50’s, V-8’s were rapidly becoming dominant among the upscale brands, but Chrysler’s Hemi’s complexity made it slow, and expensive, to build, and Chrysler’s costs were far higher than either GM’s and Ford’s. Customers didn’t seem to care about differences in efficiency. Thus, in what appears to have been a fast response to a serious problem, Chrysler created a new, cheaper, lighter, series of engines based on the Hemi. The new series was dubbed the “poly” after the polyspherical head’s rounded, circular combustion chambers. To cut back from two rocker arms to one, they put the intake valves on the top side of the rocker arm, and the exhaust valves on the bottom side. The bottom of the valve covers were scalloped so the spark plugs were accessible from the top — unlike Ford and Chevrolet V-8’s, where owners had to reach under the hot exhaust manifolds to get at the spark plugs. Overall, they were able to lower costs, and weight, while increasing production, making up for reduced efficiency with higher displacement. The poly head engines went by a variety of different names, including “Fire Dome”, “Power Dome”, “Fire Power”,” Spitfire”, and “Hyfire”, dependent upon the division. Thx.

 

   Misinformation??? Here’s some more of the original article where I obtained my information . . .

 

      Willem Weertman, the legendary engine designer, started his Chrysler engine career working on the A-type V-8’s at the then-state-of-the-art Mound Road plant. The A engine family was a modern, efficient, and durable, design produced from 1956 through 1966; the LA series of V-8 engines was based on a lightweight casting of the A engines, appearing first in 1964. The A and LA blocks are similarly sized, and difficult to tell apart from the outside, but the A's polyspherical heads were considerably larger than the LA's heads.

   The “single shaft” (Hemi-based) Poly can be identified by its separate valley cover underneath the intake manifold; the cylinder heads and intake manifolds were interchangeable with any Hemi engines that had the same deck height. A-series Poly engines didn’t have the separate valley cover underneath the intake manifold, since the intake itself performed this function. Both series of Poly engines — A-based, and Hemi-based — were similar in appearance, with scalloped valve covers, and a rear-mounted distributor, despite being from completely different engine families.

   The A-engines slowly replaced the polyspherical-head (“single-rocker”) V-8 engines: 277, 301, 331, and 354. A key difference between the A engines, and the older poly engines — essentially, Hemi engines with modified combustion chambers, and single rocker arms — was in the ease of manufacturing.

      The A engines shared little with the Hemi-based Poly V-8’s; since Plymouth’s sales were far larger than Dodge, or Chrysler, and pricing was lower, the A-type V-8 engines needed to be made far more quickly at the new Mound Road engine plant. That was a significant influence on its design. While Dodge, DeSoto, and Chrysler, had relatively small sales numbers, and could live with the slow pace of building the poly V-8’s, Plymouth’s high production required something cheaper, and faster to build. The A engines fulfilled that function, with little, if any, performance penalty. Any loss in performance could be made up for with cubic inches, and the A engines ran larger than most of the polys.

   The A engines went under various trade names including “Red Ram” “Fire Dome”, “Power Dome”, “Fire Power”,” Spitfire”, and “Hyfire”. It was an overhead valve design with dome-shaped heads. Dodge wrote, “So durable are they that the standard 25,000 mile laboratory tests for wear had to be changed to 50,000-mile, and 100,000-mile checks-because no discernible wear showed up until long past the 25,000-mile figure.”

  

   Conclusion—I didn’t write the damned article, I only quoted from it!!! Misinformation??? I DON’T THINK SO!!! Now, I AM DONE . . . .

[William Davey]

Back on topic - My 55 C-3-B8 has a 259 Poly V-8 that uses the front engine mount bolted to the front of the block. Also uses a rubber motor mount to suspend the engine from that mount. It looks like the same ones used on flathead 6, but I can't say it's identical. I second the suggestion to get every part you can from the donor car. 

[wayfarer]

44 minutes ago, The Dr's In said:

The A engines went under various trade names including “Red Ram” “Fire Dome”, “Power Dome”, “Fire Power”,” Spitfire”, and “Hyfire”.

...so you quoted something else that you found on the www...? And that excuses it ...?

 The A-engines slowly replaced the polyspherical-head (“single-rocker”) V-8 engines: 277, 301, 331, and 354.

The 277 is in fact an 'A' engine; the 301 could also be an 'A' since '301' was found in the Plymouth A engine series but it was also used in its single year production for the 1955 Windsor under the Spitfire label. So to which is the quote referring to?

The single biggest problem in todays world is that far too many folks, of ALL ages, believe everything they read/hear without having the instinct to verify the claim. The moon landing was a Hollywood set.  Al Gore famously saying the he invented the internet. Time magazine, circa 1972, warning us all of the coming ice-age.

The list is endless. Please don't perpetuate it.

 

[classiccarjack]

22 hours ago, Flatie46 said:

I bought a parts car from a local junkyard that was crushing out about 10yrs ago. It was a 47 Club coupe, someone had put a poly engine in it, they had the 3spd shifter coming up thru the floor. The engine looked like it fit well but I don't think they ever got the project going. Reason being if it would have had the fan on the engine the way they had it mounted it would have been sitting where the radiator support was. Maybe the engine could have been set back further, could have used electric fans on the outside of the radiator or whatever. I didn't really pay much mind to what had been done as I didn't plan on putting a V8 in my 46. I just pulled all I could save from this car and sent it to the scrap yard cause it was so badly rotted. Just saying I had one that had a Poly in it. The way they had it in, it didn't interfere with the factory steering.

The later poly 318's will work with the later industrial 318 water pump housing.  Just be sure to index your crankshaft at TDC to allow timing to be more achievable....

 

1960 Dodge trucks used the later poly and it had the same pump housing with the timing marks on the correct side.  Some may have used the steel pointer for timing...

[DrDoctor]

   I’ve been accused of [sic] fostering misinformation. As I stated therein – I didn’t write the damn book. I merely quoted information out of it. If the individual in question has an issue with the accuracy of the information, complain to the author, not me. Well, I think that about covers that . . .  I’ve expended much more energy on this engine information issue than it’s worth.

[Plymouthy Adams]

13 minutes ago, The Dr's In said:

   I’ve been accused of [sic] fostering misinformation. As I stated therein – I didn’t write the damn book. I merely quoted information out of it. If the individual in question has an issue with the accuracy of the information, complain to the author, not me. Well, I think that about covers that . . .  I’ve expended much more energy on this engine information issue than it’s worth.

would it be possible for you to give credit/reference to the book you are quoting?  Thanks

[dale]

Thanks for the info  DRs In  !!!

[40plyguy]

Does anyone have experience with engine mount kits that mount the engine fr the side? My friend found some listed at Butch's Cool Stuff that would offset the engine to the right. I looked at my car today and the flathead is actually offset to the right but the crank is still centered in the car. The front mount is offset to the right as well. To clear the steering column I'd have to move the V8 2-2 1/2 inches to the right. Starting to explore steering options. I don't really want to switch to R&P. If I jump into this project I want to keep it as old school as I can. I think the coolness factor of the swap would diminish w/R&P.