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55 Fargo

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I have 2 vehicles powered by Georges stuff, a 1947 P15 Sedan which has been coast to coast, even up pikes peak. 

a 1949 P17 Business Coupe similiar travels, but most notalby I ran it in a National Nostaglic SuperStock event, finishing second. (Bracket racing, driver error).  Fun Cars, not main stream.  Simple is better.   Best of luck

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These flathead motors are capable of producing good power.  On the street they're more limited in compression than an OHV motor, L-heads are not thermally efficient and will blow head gaskets when you push the limits of compression.  Respect their limits and they do better than most would expect of them.  In a lighter vehicle the low-mid range torque gives good seat of the pants response.   If they only had the displacement of the Hudson 308....

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These flathead motors are capable of producing good power.  On the street they're more limited in compression than an OHV motor, L-heads are not thermally efficient and will blow head gaskets when you push the limits of compression.  Respect their limits and they do better than most would expect of them.  In a lighter vehicle the low-mid range torque gives good seat of the pants response.   If they only had the displacement of the Hudson 308....

well they made them in 265.4 cubic inches and if I am reading the blog stuff correctly George Asche and TRim Kingsbury bored it out 1/4" so it would be over 300 cubic inches.   not sure about compression. Whhat compression can your get them at Tim?          

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10.5:1, is what Tim Kingsbury and George Asche acomplished on the 265 bored .125 over, with the, venola pistons,  head shaved etc...

is 10.5 to 1 in the dragster they have ?  if so that is likely the outter limit.  265.4 and .125 which is 1/4" I think is over 300 ci?  Or am I figuring incorrectly ?

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a tad incorrectly..at a .125 bore you do not get .250 over per cylinder...you get  .125 and when the math is complete at the max bore of this engine and leaving no room for error or rebuild without new sleeves..you get 284 cube and round up if you will 285 cubes..hardly worth the sacrifice of the block to go max build when not needed for the few CI you will net in the process at the expense of an already hard to come by block..

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There is a direct correlation between the life expectancy of a fully tricked out engine verses a somewhat modified engine. Top Fuel engines turn approximately 540 revolutions from light to light. Including the burnout, the engine must only survive 900 revolutions under load before a complete rebuild is in order. To fully trick out an engine for street use does not make a lot of sense to me unless you have a pocket full of cash and enjoy rebuilding the engine every week. I would not want to do an overbore to the maximum and squeeze the head down as far as possible for increased compression ratio in a vehicle I want to drive across the country.  

 

On a Mopar L-head engine the "bling" factor in my opinion is more important than a full out horsepower war. It is possible to add multiple carburetion, a lumpy cam, sweet sounding dual exhaust and still maintain dependability. When I pop my hood at a cruise in there are more folks looking under my hood than the guy next to me with the small block shiverlay in his old Ford. I may not win a stop light to stop light drag race but I do have a car that will run all day long at 70 MPG with the engine spinning around 2200 RPM's. It is a lot of fun passing someone at 75 MPH with my exhaust purring and shifting into (5th gear) overdrive as I pass them so they can hear the change in the pitch of my glass packs. Makes them wonder how many gears I have left.

 

My point being that for me dependability and longevity are more important than all out horsepower.

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Just a side note....the addition of more HP will also demand the upgrade of braking power and suspension response.

Not to mention possibly a better grade of tire, and tighter steering for navigating all that go power. lol

 

48D  

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Fargos-Go-Far, on 21 Jan 2015 - 08:26 AM, said:Fargos-Go-Far, on 21 Jan 2015 - 08:26 AM, said:

I believe the total overbore is .125, this would of course be attained with a .0625 boring with the end result of .125 extra diameter in the hole...

I know the total bore Fred..that was why I corrected the guy above on the ..tad of error...please read post 8 again...thanks

Edited by Plymouthy Adams
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Tim Keith, on 21 Jan 2015 - 07:30 AM, said:

A 265 with a  .125 overbore is 283 cubic inches

you must have used rounded down version of Pi or other figures.....284.0825040509055625518179496078     as many like to fudge I gave them that extra bit to round up to285...little fudge factor in their honing process...    :)

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Took Chevy to add 2 pistons and a V block to get their 283 ci......LOL

stoke Fred...all is stroke....if it were not for stoke these slightly enlarged lawn mower pistoned flat heads would not have displacement..for example the 5.3 liter V12 Jag has a .062 larger bore than the flattie 265 but with a 2.8 stroke...imagine the CID if it were on par with the flattie in stroke..

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Fargos-Go-Far, on 21 Jan 2015 - 08:26 AM, said:

I believe the total overbore is .125, this would of course be attained with a .0625 boring with the end result of .125 extra diameter in the hole...

oh and it was only .063 bore of stock block already in production that created the legendary 426....as much as I hate chevy for being short life junk their multitude of bores and strokes do allow for a great number of CI builds..

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I would much rather build a tractable engine that performs well within the rpm band typical for actually street use than one with everything peaking at 5000 RPM.  Unless your are going to be racing, or pulling a weighted sled, an engine that makes its torque and horse power north of where the factory gauged it is a waste of time and money, and will make an engine that is difficult, and likely unreliable to drive on the way to the competition field.  See it all the time at cruise ins.  Over sized, over carbureted engines that run like crap under 4000 RPM, stink of raw gas, stumble like a drunken sailor, coming off idle, and have an automatic transmission set up to not even start to pull until 2500 rpms.  Sure they look great, and sound nice at idle and at full tilt, but in between, they are basically worthless. I have a friend who has a 409 Chevy engine in a 62 station wagon.  He has more money stuck into that thing and every time he tries to drive it on the street it blows a head gasket because at 14.5 to 1 CR and way to much cam it can't run at anything under 3K. So it sits on a trailer and goes to the drag strip 2X a year when he has the time and money to pull the heads an get it fixed.  Not the way I want to use my car.  Effective carburation, moderate CR, adequate cooling, and cam'ed for efficient operation between 1200 and 4000 rpms seems to be the ticket for these MoPaR flatheads.  Anything more is trouble waiting to happen.

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well they made them in 265.4 cubic inches and if I am reading the blog stuff correctly George Asche and TRim Kingsbury bored it out 1/4" so it would be over 300 cubic inches.   not sure about compression. Whhat compression can your get them at Tim?          

As others have pointed out its not quite that many cubes, but unlike other I tend to go by the age old saying of there is no replacement for displacement.  So in that vein, Tim Keith is correct, the legendary Hudson had the advantage when they came out with their 308 ci motor which was a 4 1/2" stroke and 7.2 to 1 compression, and soon after with Dodge putting dual carbs on the truck Hudson put 2 carbs on to a car from the factory. At the time people said, why bother and it wont last. Well the answer was because they could and the engine was very capable of 100,000 miles. 

 

But back to the flathead mopar.  Using this formula from  Walter Chrysler's Chrysler Engineering Technical Manual for Cubic Inch Displacement

which is good enough for the girls I dance with.

 

 

CID = NOC x 0.7854 x bore2 x stroke

 

The big block 265 ci flathead which I have heard called all kinds of things comes out like this

 

Stock -  (3 7/16") 3.4375 bore and ( 4 3/4") 4.750 stroke is 264.497 ci

 

Here are then all of the cubic inch displacements based on over bores and obviously you can round up and down

 

Bored out

10 over - 3.4475 = 266.03838737437 

30 over – 3.4675 = 269.13408074437 

40 over  - 3.4775 = 270.68864259938 

60 over – 3.4975 = 273.81119664937 

80 over – 3.5175 = 276.95165781937 

90 over – 3.5275 = 278.52860357437 

125 over - 3.4375 = 284.08316835937

 

Stroked to

4 7/8” =  4.875  would be 291.55904121094 cubic inches

 

For me you have a couple of things to consider when over boring. Today, one of your big issues isn't with the block take a bore out as far a .125 it starts with can you find pistons and rings ?

 

They used to be easily available, but now are getting harder and harder to find without going to custom made.

 

As well once you take a block out .125 there is no next bore level so when the engine is stock and needs bored to clean up cylinders obviously you have lots of meat to bore. At .125 your at the limit.  

 

Now in terms of blocks, all blocks made in Windsor from 1952 onward are capable of being bored out by .125

 

As to reliability, while there is something to be said about taking an engine right out to the limits of performance and limiting its life span, I can provide you lots of evidence of 10s of thousands of miles on engines bored out that far and running just fine.  But of course its the age old argument by many. If I leave it rock stock it will last longer, so I should leave it like that, as the other guys says, well maybe but I want more power out of this engine.  Everyone has to decide where they are on the risk vs reward scale.   While there is no right or wrong answer I am definitely further to the right on the scale !

 

 

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Just a side note....the addition of more HP will also demand the upgrade of braking power and suspension response.

Not to mention possibly a better grade of tire, and tighter steering for navigating all that go power. lol

 

48D  

It is a very good point. You can get into way more trouble not stopping than not starting.  So as I covered in the blog on the car being referenced here. 12" Chrysler brakes from a vintage Chrysler, a sleeved master cylinder, new lines, new shocks etc were definitely key components.  But they of course we all know I wont be breaking any speed limits on public roads just like everyone else here so its not a major issue I guess.. lol

 

Truth is I think all of that is important, even though compared to some of the braking systems of Ford and Chev, Mopar was way ahead of the pack. Improving the breaking system, even if its just sleeving the master cylinder and making sure its got great lines etc is important so great point  !

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Everyone is talking about the big block Chrysler engines which are two inches longer than the 218/230 short block.  I think for longevity the long block is the better even in the smallest displacement as it does not have to use off set rods.  I feel that the off set rods place a higher load on the rod bearings verses the inline crank throws with the cylinder bores on the long block engines.  I have been told by many old timers that the Plymouth and Dodge engines had soft cranks.  Since most of the people telling me this drove company cars possibly with dubious maintenance out in the oil fields of the west.  I have modified my 218 in many ways and run it hard on the highway having taken one trip of 4800 miles with very little drama.  The only damage the engine has suffered has been self inflected by the owner, such as running 10 degrees static timing over the 4800 mile trip and installing the number one main bearing shell without the hole in the upper half of the journal which caused the number one rod bearing to fail.   These engines are tough engines.

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These are good motors.   With better head gaskets the compression could probably be increased for a daily driver, but I'd focus on matching the gears to the torque and installing in a light car.   With todays motor oil and improved metallurgy for the pistons you can expect to see greater longevity.   I think George Asche told me he had a '51 Plymouth with 218 that has over 200,000 miles on a rebuilt motor.    Most of us don't drive these old cars on a daily basis, but you could do that.   That's the kind of performance that interests me.

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